I'm building a 275 drag radial car for next year to run in some local classes. I was looking into the AES forged 5.3 motors, either 323ci or the 364ci short blocks. I was wanting to run aftermarket heads, but not sure which direction to go as most have not really done built 5.3's at least from what I've read. Also the class is limited to a single turbo 76mm with non billet wheels. These classes run 1/8 mile tracks mainly. So for turbo selection would i be better off with a large frame like the BW S475 or a mid frame like a PT7675? The car has a 3400# minimum for my setup. It is a full suspension car with moser 12 bolt 3.50 gear, PG trans, A2W intercooled, and stock PCM for engine management. Car will be ran on e85 or e98 (dependent on availability) Any advice or comments on heads/turbo or engine combos in general would be appreciated. I will also note that it will need to be in the 5.30-5.40 range to be in the head of the pack.

 

Depends if the class allows clipped wheels or not. If so look for a custom thumper turbo turned down to 76 (class turbo). I don't think either of the turbo's you listed will compete. If you're not allowed to run a clipped wheel than either a GT-4776 would rock or the new BW 76mm cast wheel with a T6 92 or 96mm turbine wheel. I don't see a T4 competing with cars running 5.3-5.5 at that weight.

Here's some info http://www.yellowbullet.com/forum/sh...highlight=76mm

 

What is the cubic inch limits vs. weight for your class? (when using a 76mm turbo)

 

make sure you can use e85 over hear we cant use e85 and if your not running a 5.00 down here your not going to be competitive...p.s im buildling my coupe for x275 as well Good luck!!

 

No clipped wheels allowed. Ci limit is 427ci. Turbo sb is 3200 50lb penalty for aftermarket heads, 100lbs for a2w. And I planned on Holley efi which is another 50lbs. Anyfuel type is allowed in the class. It is a step under x275 we call it 275RS (real street).