Hi have been running a small single turbo on a bone stock chevy 350. It had .080 dish pistons with 487 heads. While i got the motor apart, im debating on putting flattops in it with 062 vortecs, i know this will bump up the compression ,but with the realtively small hx40 (58mm) compressor and a tighter quench area. 015 head gaskets and being conservative on timing would 9.7to 1 comp be too much.Have my eye on a comp 268h cam to go with the heads. Iam also considering running e85. This is just a mild 12 .0 sec car shooting for 11.50 s. I viewed your post on those ported vortecs and thats what gave me the idea. im planning on about15 psi of boost . Your chevelle is an awsome machine , after i get tired of messing around , a s400 bw will be next, any help is appreciated .