Originally Posted by AZScoobie
US STI heads are around 57cc combustion chambers, EJ205's are around 52cc, V7 and V8's are a tiny 48-49.... You really need to lower the compression with pistons or with Gaskets at least. If not you will be limited on the boost you can run. This makes a huge difference on a GT35R that does not want to be at 14 psi...
Clark I'm running the V7 Big ports with a 2.5L bottom, are the combustion chambers that small on the BP's as well? Also although the V7 heads were designed to run with a 2.0L is there any other disadvantage to running them on a 2.5L?
Lastly would I see more advantages running an UTEC with stock 02 ECU (no AVCS) or stepping up to a Hydra and running the AVCS. This currently powers a 18g 8cm but will be a Red 8cm soon.