just building a 406, with a mild cam, looking at the XFI by comp, with a .584 intake and a .578 exhaust for lift with a 1/6 ratio rocker. this is just a baseline cam i kinda picked out. the pistons are flat top forged SRP's and Scat 9000 crank and scatt forged rods. I'm looking at buying some AFR 210's with 100% cnc machining. pretty big for my motor, but i'm wondering how they will be for a supercharger. i have a pretty high compression, of approx 10.5 :1. I'm just wondering what the max psi you can run with this. on pump gas ( 94 octane) i already plan on having to use that or near that to run the motor anyways.

cheers

blake

 

with the compression you will have i would look at the blowers for the LT1s for the answer, the ones i see only produce around 4.5 psi, hope this gives you a starting reference.

 

compression is WAY too high.. MAX boost should be 5lbs intercooled.. get some .060" thickness gaskets and heads with at least 72cc.. that should bring the compression down to "ROUGHLY" 9.5:1.. then boost can be turned up to 12psi.. maybe 15psi..

 

well the heads are 76cc, i'm trying to go as big as possible on the CC size

 

76cc is usually the largest you can get.. was the compression ratio 10.5:1 with the 76cc heads?? i hope not..

 

I assume you have the pistons already? Damn, if you can i'd look hard at replacing those. If they're pricey pistons, might be able to get a machinist to cut some dish in them.

And yea, biggest heads you can find. Try not to go too high on gaskets, don't want to toss quench all out the window.

I'd forget about using forced induction if you're over 10:1 SCR. You'll barely get anything out of it before you're REALLY running the ragged edge. 4psi as mentioned.
I'd much rather see you using 8.5-9:1, and 12psi or something, and making like 800HP. Sounds like a good cam, I think the XFI have the wide LSA right? And a nice split pattern? Sounds good. With the 210's on a 406 and the blower, I see big numbers out of that beast.

 

well perhaps that can be something down the road, because in reality.... i have a cast scat 9000 crank. best to go with a very good forged, and get some nice h beam rods, and might as well get a good aftermarekt block as well hey? and then have it all properly balanced, maybe then i'll think about supercharger. but i tihnk these heads woudl suit that great. on DD2000 these heads make about 550 hp n/a sounds about right. when it comes time to buy the cam, i will be calling these cam manufactures up the ying yang ( I have time, i'm a full time student) and get what sounds to be the best suited one. perhaps a custom grind will be recomended. i'm going with an HSR and using a mega squirt set up