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Vorshlag Budget 2015 TT Build: Project DANGER ZONE

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continued from above

 

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Could we have rebuilt the OEM Delco-Bilsteins instead? Sure, but there were two problems with this idea. First, the time frame we had to build this car back in January (2 weeks) wasn't going to give us enough time to have the old shocks rebuilt. While we are a Bilstein Motorsports dealer, we still don't have the $5000 fill rig necessary to refill the Nitrogen charge in this particular style Bilstein (and that's all it works on). Secondly, if we had said we had these shocks rebuilt, who would have believed we had kept the OEM valving?? We make and sell shocks for a living! That would have been the first thing people assumed - shock guys, cheater rebuild.

 

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These have been sitting in a box in my office since January, in case we were forced to rebuild and use them.

 

The proof about what came in the 1992 model base coupes is shown below, which are some pages from GM documents which I haven't shown before (Jason researched and found this cache of GM documents for the 1992 model Y-body). There are hundreds of pages of period documents on this version of the C4, so have fun digging.

 

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We knew these Delco-Bilstein monotubes were the stock dampers but apparently some folks didn't even believe that. So I'm showing this now, since I was warned that I'd lose a protest even if we put these old blown out shocks back on without showing documented proof of the OEM fitments. Guilty until proven innocent, but I guess with a build shown this publicly I should expect this level of scrutiny.

 

After looking for the exact OEM replacement shocks back in January we found that we could no longer buy these Delco-Bilsteins anywhere, for any amount of money. Not from GM, not from Bilstein, and there were no "New Old Stock" dampers available anywhere (if you find any, please send the link my way!). So, from my SCCA background on similar "stock replacement equivilent" issues we "assumed" that a close alternative replacement to the OEM dampers would be allowed. So we looked and found a set of shocks that were the closest and still available new: Bilstein B6 monotube dampers that are listed in the Bilstein catalog for the 1992 base trim level Corvette. These are a whopping $85 per corner, retail, and we paid less that that with our direct dealer account.

 

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And while I didn't go into this excruciating level of detail before, I hid none of this. We showed these B6 dampers in one of my first posts here, but I didn't show that there are about a dozen choices for the C4 from Bilstein... they make some for the base model, others for the Z51, some for different years, there's a B6 and a B8, and of course fronts and rears. This array of cheap Bilstein monotubes is what we chose from to get the two part numbers shown for the 1992 base model coupe, shown above left.

 

These are painfully similar to the OEM Delco-Bilsteins - they have the same 46mm pistons, same 50mm body diameter, the same shaft sizes, same body dimensions, and no external valving adjustment. You can see the details in the images below, which were captured from the "GM Heritage Center" database of records for 1992 model Corvettes at this link.

 

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I have cleaned up these scans from 24 year old literature published for this 1992 model Corvette, and even highlighted the mention of Delco-Bilstein (its referenced on 6 different pages) and even the dimensions of the shocks. And the swaybars - which are still the OEM units. These Delco-Bilsteins are functionally identical to what we have been using (the $85 B6 dampers), but that's not good enough to be legal as +0 point shocks, they have to be the actual 24 year old Delco-Bilsteins, which we'd need a TIME MACHINE to get a hold of a new set in 2015.

 

GM doesn't keep original stock parts on hand for more than 10 years, but they instead have a "generic replacement part number" that supersedes the original 1992 shock part numbers. This replacement part number is shown for all 1989-1996 Corvettes without the adjustable (FX3) dampers. Its a $28 piece of crap twin tube shock that is so dissimilar to the 1992 model OEM damper that its almost funny. Not gonna happen on my car, no way.

 

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Anyway, long story short - we are now sending the old and blown OEM dampers (shown above) directly to Bilstein, having them rebuild them, and then asking them to include documentation that they didn't alter the valving in any way. I'll have them seal the shocks in tamper-proof tape if they can, too. And someone will probably still accuse us of cheating, oh well. These "cheater" B6 Bilsteins will be for sale here soon after - cheap!

 

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I wish I could take people for a ride in this car on track with these B6 Bilsteins. Well, with no right seat that ain't gonna happen. Any way, the C4 on these shocks rides like a big underdamped mess at speed. This is not a great set of dampers, not by a long shot. But they are just the closest thing we can find to OEM that isn't leaking. At $85 per corner, you get what you pay for. But that's not good enough - I have to use actual OEM shocks, not OEM replacements, or take +2 points (and move to TTB). And the burden of proof is on the DRIVER.

 

Whatever the answers to life's big questions, we're going to make SURE this car is squeaky clean at Nationals. If I get protested over some bullsh*t non-performance hidden rule detail, I'm going to share it here for all the world to see. Hopefully, after this 5 part protest and the resulting changes we will make to 4 items, it will be smooth sailing from here on out.

 

What's Next?

 

We're desperately trying to get the motor back and installed in time to make Hallett June 13-14, but time is not on our side. I'd also like to get the following changes, modifications and completed before NASA Nationals East:

 

  • Since my red Suzuka trade fell through after the fact (not my fault), we have to install a new driver’s seat (black Cobra Suzuka GT width Kevlar seat just arrived)
  • Add a massive oil catch can + breather system to the motor
  • Add oil temp sensor (OEM dash) and level gauge (external)
  • Order the 1994-95 wiring harness and switch to a 95 Corvette ECM to help with tuning
  • Install poly bushings throughout + machine offset Delrin bushings where needed
  • Design and build front brake cooling + new braided brake lines
  • Add windshield defroster box and new aqueous foam fire systems to complete safety updates
  • Build support frame for rear plexiglass hatch and install
  • Move full sized battery to rear cubby hole + rewire main battery cable with main power kill
  • Make aluminum covers for ABS and battery cubby holes
  • Move ballast weight rearward
  • Take car for interior paint + cage paint, exterior repairs + left side and front end paint
  • Complete the new livery package with stripes #RAMPAGE
  • Spend last point on proper custom cold air and hood venting

 

Lots planned before Nationals, and some of it might be protest bait, so we might hold off if it seems unnecessary. Again, the way that the internet protest went down was a bit weird, but look at this build thread - the pictures, the details I'm sharing, the SMACK talk in my first post? I probably should expect this level of scrutiny more often.

 

That's all for now - will update once the motor is back! Thanks for reading,

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Project Update for August 21st, 2015: Its been almost 3 months without an update, and while we have knocked out a few things on the C4, mostly we have just been waiting for the rebuilt motor to arrive. We're less than 2 weeks from NASA Nationals East and I had hoped by now to have the motor in, a few race weekends of tuning under our belts, and ready to go to VIR "fangs out". But a big delay on the motor has crushed our hopes and dreams a bit, heh. Read below to find out where we are on this project.

 

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But first, in celebration of Grassroots Motorsports magazine's annual "Wear Your Helmet To Work Day" (Aug 21, 2015), I give you our submission we took this morning at Vorshlag. This shows almost everyone here "working" on the 69 Camaro Pro Touring / Track Car we're building for a customer (latest update here). That was fun and GRM shared our picture at the top of their page of submissions on Facebook. Installing an intake manifold on the roof like a pro? I think we nailed it.

 

The Best Laid Plans...

 

So back in early May I had hoped for a quick 2-4 week turn around on the very basic rebuild on the 24 year old LT1 motor. Paid up front to help speed things along at the machine shop, too. I really wanted to make the June NASA event at Hallett, because if I could have made that event (and scored points both days) we could have salvaged a chance at winning TTC in the Texas region season points battle. We only get 4 "drops" for the year in region, and with the issues we had at MSR-Cresson in March I didn't get any points either day, so that's 2 drops. Then we missed the "last ever" NASA event at TWS in April (we ran the TT3 Mustang for one last time), so that's 2 more TTC drops. Making Hallett would keep us in the points...

 

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Nope, that deadline came and went. Its been 14 weeks since the motor shipped out to the machine shop, but I keep hearing "pretty soon". Pretty disappointed, and if the motor doesn't arrive in the next handful of days we miss NASA Nationals East (13 days from today). We are moving forward with every hope that the motor shows up, then we can thrash to get the drivetrain reinstalled, get the dyno tune re-checked, install the new Peterson oil catch can (below), then rush out to ECR or another local track for some shake down testing. If it looks good there, then we'll pack up and tow 17 hours to VIR for NASA Nationals East September 4-6, 2015.

 

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But seeing that we would have to leave in less than 13 days, and I have no motor, I kind of doubt we will make it. Some valuable lessons learned, mostly "take your motor out the day after it breaks" and "use a local engine builder" who is close enough to knock on their door. Daily. Oh well, fingers still crossed. Let's go ahead and cover the work we've done in the past 3 months to this car. Even if the motor returns after Nationals is over, we will still try to make the 2 remaining NASA Texas events for 2015, just to see how it does in TTC before the chassis is re-classed in 2016 (likely to TTB or even TT1/2/3).

 

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Did want to give a shout out and congrats to Dave Schotz. He took his TTC C4 (built at the same time as our's) to the 2015 NASA Nationals West a few weeks ago and won both PTC ant TTC in his Corvette. He also took the wins in PTC and TTB in his 4th gen Firebird. That's 4 championships in one weekend! Way to go Dave.

 

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The fact that he won TTC/PTC in a C4 pretty much guarantees that the car will be re-classed next year. So that's not good news for us if we miss NASA East this year. We had one shot...

 

Old Shocks Rebuilt and Reinstalled

 

If you couldn't tell from my last post where I discussed the "the 5 Point Mystery Internet Protest", I didn't agree with many of the items that were ruled against this car - ruled upon sight unseen, after being protested by a competitor with their name withheld. Oh well, now we all know what to expect when you race in the same class as the _____. (you can fill in the blank)

 

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We got to spend $450 getting the 24 year old factory Delco-Bilsteins rebuilt by Bilstein-USA. Since we paid for a rush it only took 5 weeks to get them back, hoping that the motor would arrive in that time. Money well spent - these sat around for only 2 more months before we even installed them.

 

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Biggest difference in the OEM vs OEM replacement Bilstein dampers sets? Blue vs Black dust boots. #CheaterShocks

 

We made sure to get documentation from Bilstein, showing that they only replaced the seals and wear items. The original shocks' shims and pistons were left alone. But who cares? Nobody believes anything they read on the internet anymore. These pictures are probably only good for use against me in a future internet protest, hehe.

 

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Olof swapped out the "new" $85 Bilsteins replacements for the $450 rebuilt 24 year old Bilsteins in 1.27 hours of non-billable time. They look identical to each other, but we didn't bother to dyno both sets to prove how equally pitiful the two sets felt. I'm sure they are just as floaty as the "new" set was.

 

8.5 BTM (Base Trim Model) Definition, Updating and Backdating Rules

For the purposes of NASA TT Modification Points assessments, the term BTM will be defined as follows: Any part that is identical in size, shape, and functional characteristics compared to the part that originally came on the vehicle, from the manufacturer, as a standard feature of the base trim model as it is listed in section 8.2 Base Classifications (factory options and specialty model parts are considered non-BTM) or is listed as a standard replacement part by the manufacturer (OEM).

 

Some parts that are produced by aftermarket manufacturers as generic replacement parts may not require a points assessment provided that: they are the same size and shape, and have the same functional characteristics as the BTM part, and that they provide no significant improvement in performance, longevity, or reliability. If it is determined in impound that such a part does not meet the above description, the driver may be disqualified. Consultation with the Regional TT Director prior to competition is advised for any driver using a vehicle with replacement parts that fall under this exception.

 

This is sufficiently vague as to mean "we can pick when we want a replacement part to be legal". We learned from this ruling and the precedent set that: unless you are using the original, as-delivered factory base trim level shocks on your TT letter car, you should just take 2 points for whatever shocks you have installed. There is no "OEM equivalent" for these mysterious and mythical parts called "dampers". You were warned.

 

Remove Cage Tubes

 

Speaking of wasted hours, Olof spent another 2.4 hours taking these roll cage bars out. Yay.....

 

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Again, I completely disagree that these two optional bars forward to the firewall aren't 100% legal (again, without taking points we didn't have). They were installed as no-points tubes to the letter of the rules, but the "unwritten" wording is what got us. They weren't below the top of the tire, which is true - even if that phrase is nowhere in the NASA rule book.

 

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These two optional bars connecting the door bars to the frame on the passenger side weren't legal without taking points. I still think its silly to encourage asymmetrically safe cages, but we pulled those two bars out.

 

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Once the 4 tubes were cut out the flapper wheel on the electric grinder was used to get the stubs of tubes smoothed flat. It took time and made a huge mess, but there's now no sharp edges to catch a driving suit or cut your skin, if snagged. And more importantly, there's no nit-picky visible items to protest. #CheaterCage

 

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Cutting and grinding the cage to get these tubes out made a lot of metal dust, which went everywhere inside the car, so Olof spent another 1.15 hours cleaning out the entire interior. With some oil that was spilled in the floor on the passenger side (when "Old Smokey" was giving its last death throws at the NASA MSR-C event), and piles of metal dust, it made a real mess. But he got it cleaned out and ready for the replacement Cobra Suzuka GT seat - which is here and going in later today.

 

continued below

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continued from above

 

Engine Bay Power Wash + Seat Swap + Firewall Re-seal

 

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Having the drivetrain out sure makes for a perfect time to clean two+ decades of crud out of an engine bay. This one had it all - oil, dirt, funk, and grease. Brad rolled the car out back and fired up the pressure washer in 105°F heat and got it blasted clean under there.

 

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Once inside I used my "WD40 all the things" trick to shine up the old painted surfaces and rubber. Let that soak then wiped it down.

 

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After the cage tube removal mess we cleaned the glass inside and out with Windex and newsprint, to polish the glass. First time I've been able to see out of the glass in all directions without looking through some film of decades-old funk.

 

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Today Olof installed the new Cobra seat (the red one went away) and then re-sealed the firewall. There is an aluminum panel where the old factory blower motor/heater core box was in the engine bay, and it leaked a bit of oil into the passenger foot well when the motor smokified. That's finally water tight and should be leak free.

 

Now we just need a motor...

 

Aluminum Griffin Radiator Upgrade

 

One of the things I had hoped to do at VIR was take a lot of laps. I have never driven that track and it has a LOT of turns, so I was hoping to make every session from Friday-Sunday, to learn the line and hopefully put in a good time. I was going to take 2 or 3 sets of tires on 2 sets of wheels, too.

 

8.3.I.c.3) Radiator upgrade/shrouding/fascia modification (drilled or cut holes/slots) that only provides increased airflow to the radiator or oil/transmission coolers (without aerodynamic or engine air intake improvement), and/or radiator core support modification/replacement

 

To ensure that the car ran smoothly for longer stints on track at VIR, I wanted to upgrade the radiator. This is FREE in TT-letter class, by the way, for all of you rules Nazis looking at this build (see the "No Points Mod" rule above, which is from page 35 of the 2015 NASA TT rules).

 

The stock radiator is already pretty sketchy design, with a tiny aluminum core and glued plastic end tanks. They fail over time at the tank to core junction. This looks like the original piece, too. So I looked at direct fit C4 radiators that were all aluminum and beefed up in size. $545 for one, $625 for another, and all of them would take 6-8 weeks to be built. Nope!

 

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The OEM radiator is bundled with the A/C condenser (already removed) in this fiberglass, factory duct box. It has no filler neck, as the car has a remote coolant reservoir tank higher in the engine bay. The two fans and shroud look sufficient, and don't do anything at speed anyway. I measured the radiator core size and did some searches...

 

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We used the generic Griffin aluminum radiator for a mockup in the 69 Camaro (left), which fit that frame spacing well

 

Summit Racing catalog has 2,312 different aluminum radiator listings just from Griffin. So I picked a NASCAR style Griffin radiator of the same basic height and width, with the same inlet/outlet layout, but with a massive 3" thick dual core. This was a $175 retail part, now we just had to modify it to fit this car...

 

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Olof then modified the "generic" radiator to fit inside the C4 shroud and frame layout. The lower radiator hose was angled, so that was cut off and the hole plugged. It needed to move upwards a few inches to clear the front cross beam (see below), so he drilled a new hole and moved it there. Then he modified the fiberglass radiator shroud/housing/mount to clear the inlet on the top left corner. The radiator neck was cut off and capped, then a matching "steam line" was added. This was done with a weld bung and re-using the fitting that came with the Griffin, which was threaded into the water neck for the overflow port.

 

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It worked out great and took a total of 4.05 hours in total for Olof to: remove the OEM radiator assembly, modify the radiator (cutting and TIG welding), pressure test the modified Griffin unit, modify the brackets/mounts inside the fiberglass shroud, and reinstall everything. In the end we got a LARGER capacity Griffin radiator that fits better and is bigger than anything we could have bought that was a direct "bolt in" for the old C4.

 

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During that 4 hours of work Olof also made an aluminum cover for the gaping hole in the side of the fiberglass box where the A/C bits passed through (visible above left). The new radiator was bigger in every dimension just enough so that it barely fit in the fiberglass enclosure, and there wasn't even room for rivets to hold this panel on - so it was bonded with epoxy and held in place while it dried with the green tape. There were also weather-strip seals added next to the new radiator to better seal it to the inlet/outlet sections of the fiberglass duct - that should be better than the factory airflow management in the radiator box.

 

We're really ready for the motor....

 

What's Next?

 

I just heard back from my engine builder minutes ago, and he says the last "hard to find OEM LT1 engine parts" are finally there. He's supposed to be wrapping up the motor this weekend, then bring it personally to our shop since its so late (no time for pallet shipment). So I'm hoping he's right, and we might, just might, get this car together in time to make VIR in 2 weeks. They need my entry for TTC to "make a class" at Nationals, so others are counting on us to be there, too.

 

We had a lot of other plans we would have implemented if this car was put together 2-3 months ago, like we had hoped for. Things that are small incremental improvements in weight balance, airflow, safety, etc. But with virtually no time left to test even if the motor showed up tomorrow we're holding off on more changes to the car. Too many changes means too many risks of something done that fails - and I cannot afford for any failure if we make it to VIR in 2 weeks. I need an uneventful weekend with lots of track time, some good lap times, and no trivial protests.

 

Now we just need a motor...

 

More soon,

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phastafrican

Disregard if already taken into account, but perhaps an easy addition to eliminate any questions as it jumps out at me.

 

PT/TT Rules I.f.6

 

... All ballast must be of solid material (no fluids or shot pellets) and safely secured in any location on the vehicle approved

by NASA safety technical inspectors. The preferred method is to use at least one (1)

3/8-inch grade-5 bolt, two (2) “fender” washers and a locking nut system for every

fifteen (15) pounds of weight. (supersedes Section 15.20 of the NASA CCR)

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loftygoals

Are you planning on being at MSR-H? I'm looking forward to competing on a weekend when we both have fully operational cars!

 

-bj

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kbrew8991

the mounting plate underneath the weights seems to have many bolts...

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phastafrican
the mounting plate underneath the weights seems to have many bolts...

Certainly one way to look at it.

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PoBoyR6
Disregard if already taken into account, but perhaps an easy addition to eliminate any questions as it jumps out at me.

 

PT/TT Rules I.f.6

 

... All ballast must be of solid material (no fluids or shot pellets) and safely secured in any location on the vehicle approved

by NASA safety technical inspectors. The preferred method is to use at least one (1)

3/8-inch grade-5 bolt, two (2) “fender” washers and a locking nut system for every

fifteen (15) pounds of weight. (supersedes Section 15.20 of the NASA CCR)

 

Smells like another protest Terry! Might I suggest your next build is held in an undisclosed garage with no windows, no pictures taken and anyone working on it has to sign a non-disclosure agreement. A couple BEWARE OF DOG signs wouldn't hurt either.

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Smells like another protest Terry! Might I suggest your next build is held in an undisclosed garage with no windows, no pictures taken and anyone working on it has to sign a non-disclosure agreement. A couple BEWARE OF DOG signs wouldn't hurt either.

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Hehe.... yea, if they have to protest our ballast box, then someone is a pretty sad sack. But I don't put it past the internets. (Note to protest trolls: the two tubes attaching the door frame on the passenger side to the frame rail have been removed - its an old pic)

 

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Somebody complained (online, of course - where the REAL experts reign supreme) about the ballast box in our TT3 Mustang (above), also. We tested this by picking up the back of the car with the frame. Nobody in tech ever bats an eye when they see either ballast box in person.

 

Are you planning on being at MSR-H? I'm looking forward to competing on a weekend when we both have fully operational cars!

 

-bj

I sure want to to make MSR-H and TWS in the Corvette, but my engine builder is working at a glacial pace (4 months and counting). Already missed NASA Nats east, which burns my ass. Lately the motor has been held up waiting for a replacement 1992 LT1 camshaft (which is unique to one year, of course). The short block and heads are complete, but I'm never showing any pictures of those here. If people want to see inside this basic rebuild, they can pay for a tear-down at protest. I need to be as secretive as my competition.

 

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Meanwhile we've started another TT build, on the BMW E46 325Ci above. The build thread is on 5 different forums, but I will never post another build thread here on the NASA forums. Not giving the protest trolls here any more red meat.

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loftygoals
I sure want to to make MSR-H and TWS in the Corvette, but my engine builder is working at a glacial pace (4 months and counting).

 

4 Months for a SBC? Aren't those just held together with bailing wire and hose clamps? I think my 2 year old could get a LT1 assembled in less time than your build has taken.

 

Anyway, I hope the stars align and you make it.

 

-bj

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kbrew8991

yeah, nobody has Google to go find your other build threads

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Fair
yeah, nobody has Google to go find your other build threads

 

True, but I think most protest trolls are super lazy. They can't even drop paper in person, they just want to send an anonymous email. I'm not going to make it THAT easy any longer.

 

This forum uses jacked up UBB code as well, so I have to do several search/replace edits on the code to make my posts with images and links work here. Bah, nothing but grief.

 

If others want to see the rest of the updates to this build, you can see the forums where this thread is still being updated here: http://www.vorshlag.com/forums/showthread.php?t=8341

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