The thing about putting together a combo is that it's never as easy as it sounds. I don't think I would try the 33cc dished pistons with the AFR heads. You'd probably start to have a problem with quench. 8.5 to 9:1 is really about all you need with a FI street car to run on pump gas. You'd be really surprised at what 12 psi will get you.

96LT1, I'm not sure what you mean here...

383 w/ heads/cam and 150 shot sounds fun.... but how much will the 383 lose N/A that it could have w/ a smaller(?) dish piston and higher compression? This FI the more I read seems like such a hard project that its not even worth it.... is that the truth?

FI isn't a hard concept. It's doling out thousands of dollars in parts and labor that most people can't handle.

 

I meant, in an N/A application how much more HP will the 383 w/ 10.8:1 compression make than the one w/ 9.0:1

If the 9.0:1 383 makes a lot less (which I'm pretty sure it does) it wouldn't be worth making it unless I had the bottle/turbo ready... if it is not much of a difference though, it would be worth building it w/ low compression first off and wait till I have the money for turbo/nitrous.

 

I believe the general rule of thumb is that if two motors are built the same with compression being the only difference, you will gain or lose 3% for every full point of compression. It's not a whole lot, it's really all in the heads and cam.

 

It's not that large unless the initial CR is very low. As the CR rises, each incremental is less. IOW, going from 5:1 to 6:1 is a 20% increase but going from 10:1 to 11:1 is only 10%, and so on I have the table somewhere if anyone is curious for the real numbers. In the usual range is 1-2% per point.

Rich Krause

 

I'm planning on rebuilding my motor also. Here in my town there is a great shop for stock engine parts (one of the cheapest in the country). I'm picking up the complete short block kit for $373. It comes with alot (pistons, rings, cam, crank, gaskets). I'm also picking up reman. heads for $335. They are all stock spec. though. If you want perf. you need to add $$$

 

I knew it wasn't alot. Had to guess since I'm here at work. BTW, does anyone except top fuel cars run 6:1 or less? Do top fuel cars even run that low? Last I heard they run like 40 or 50 pounds on those big roots blowers.

Robert K is right. + = $$

Ps. We need more smileys in this forum.

Pss. Rich, at what point (head chamber size/piston dish size) would one start to have a problem with quench? 93z96svt was wondering about problems using SRP/JE 33cc dished pistons with AFR 76cc heads. I don't think it would be a good idea, but I've been wrong before.