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AI sn95 Engine Build Suggestions


FlyBoyGeo

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After several phone calls with some engine build shops, it appears the 331 is the way to go in a road race engine. 347 longevity due to rod length, sustained high rpms, engine braking and a weak block was touted as a big negative. #2 main cracking.

 

It's time for my factory 302 engine to get replaced or refreshed in my AI sn95 Mustang. What are your suggestions? As most, I'd like to get the best for the least amount of money.

 

I'm shooting for 3100lb race weight so need approx. max 335hp / 354tq. EFI setup. No Coyote swap.

 

I'm thinking three options:

 

1. Stock block 302 with a good head, cam and intake (Trick Flow or AFR), arp main bolts and a good top end kit with supporting mods. Run it for 2014, look around and save up for bottom end. Not maximizing hp/tq for class.

2. Built stock block 331 with forged internals and good top end with supporting mods. Keeping fingers crossed about not cracking block. hp/tq numbers where they need to be.

3. Spend the big money now up front, Dart SHP block, forged internals and a good top end with supporting mods. hp/tq numbers where they need to be.

 

What are you experiences in Windsor builds? What would you recommend and what do you regret?

 

Thanks for you suggestions and input!

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Look up UBR racing... you can find their link on facebook, etc. They are in Missouri/Ohio area, and are pulling a newly rebuilt Ford Boss block 347 stroker out of their s197 car. Selling it complete for a great price, along with a tko600 with road race gearing. Worth checking out. Any stock block is not going to last long at AI levels... Lots of 347's out there in AI cars. Mine included...

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I'm running a 302 based 331. It's a zero balance motor based on an Eagle crand, H-beam rods, and Mahle 3.3cc dish forged pistons. I'm using 0.027" Cometic head gaskets and AFR 165's (61cc) 1.90/1.60 heads. That nets right at 10.0:1 with a 4.030 bore and 0.012 top of piston to deck. With long tubes and an x-pipe, I'm expecting 340/360 with this combo. The rotating assy was spin balancedand I'm running an aluminum flywheel and ATI balancer. Intake is a TFS "Track Heat" with 30# "red top" FR inejctors, 75mm T-Body, 80mm MAF, and a large conical air filter. Headers are BBK Longtube (1 5/8" primaries). Cam is a catalog cam from Comp Cams with a wide LSA and moderate duration and approx 0.550 lift with 1.6 FR roller rockers.

 

When tuned, this makes 300 ft-lb from 2000 RPM thru the powerband.

 

Good luck with whatever you decide.

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A stock 302 block has very thin webbing at the mains. Typically, they don't hold up to sustained RPM's and/or stroking, even to just 331. I would recommend a 4 bolt main block (Boss 302 block is a good option, there are others) , and would even consider a stock 351 ( be sure to get the main bearing clearances correct) before I would use a stock 302 block.

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Ed - Thanks I have been in contact with UBR Racing.

Marshall - I appreciate the detailed response.

Dave - I agree, I need a great bottom end to work on.

 

Thanks for the responses. Any other input?

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Go with the 347 circle track crate motor from Ford Racing. I've got 4.5 seasons on one and haven't even taken a valve cover off... I converted it to FI right out of the box but you wouldn't have to do this... Just my .015.

 

Ed

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I would agree go with the 347 but heck I might be bias lol. Your going to love it.

 

Mark,

Is the 347 Ford crate engine based on a stock 302 block ? Is it a 4 bolt main, and/or any other improvements over stock?

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  • 2 months later...

Ed,

 

Thanks again for the suggestion!! I was able to get a great engine from Mark. Swapped it to EFI, and sn95 nonetheless, finally putting it back in the car soon.

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  • 1 month later...
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My combo (above) ended up making 370HP/372TQ unrestricted. We put it on a throttle stop and got it down to 325HP/349TQ for my power/weight.

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My combo (above) ended up making 370HP/372TQ unrestricted. We put it on a throttle stop and got it down to 325HP/349TQ for my power/weight.

 

I am liking the throttle stop idea better than a restrictor plate. Did you fab one up or purchase? Any pictures?

 

I have not yet dyno'd the engine, but at my last event it pulled hard and strong.

 

Thanks Marshall

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My combo (above) ended up making 370HP/372TQ unrestricted. We put it on a throttle stop and got it down to 325HP/349TQ for my power/weight.

 

I am liking the throttle stop idea better than a restrictor plate. Did you fab one up or purchase? Any pictures?

 

I have not yet dyno'd the engine, but at my last event it pulled hard and strong.

 

Thanks Marshall

 

 

The throttle stop was literally a piece of aluminum bushing material that spaced the throttle bracket away from the throttle body, effectively shortening the stroke of the cable. Took all of 5 minutes. We just ended up getting the size of the bushing right on the first try.

 

1544567_10200765765785873_1802674642265551577_n.jpg

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