JesasaurusRex

K well ill be getting some afr 210s probably, might be 220s but anywayz. Also gonna get a solid roller cam with these specs

Operating Range: 4500-7500 RPM
Duration Advertised: 313° Intake / 322° Exhaust
Duration @ .050'' Lift: 276° Intake / 284° Exhaust
Valve Lift w/1.5 Rockers: .660'' Intake / .630'' Exhaust
Valve Setting: .026'' Intake / .028'' Exhaust
Lobe Separation Angle: 106°

Going into a 400 sbc. Now I wanted to know whats pretty much the highest (while still leaving slight room for error) amount of compression I should run with out fear of detonatation. Needs to be 91 octane proof since thats the highest in dumb ol Cali. But ya. Quench will be HOPEFULLY around .040 but might be around .060 depending on if I get the block decked or use a .015 head gasket. Um pistons will be some forged flat tops well c what in the future. But anywayz wanted to know what you thought i should run max compression with out fear of detonation on 91 octane. THanks bro. Oh also just by curiousity what do you think is the lowest I go if i some how just feel in the distant future I should want to throw a blower/turbo on it. Thanks bro.

69z-28

im not arch and idk what octane u need but here in illinois, my dad gets premium in his car and it runs fine. he is pushing about 10.25:1. id say you can prolly go like 10.5:1 and still be safe if you have the same premium we have.lol and like you said you can always get a thicker head gasket. but if you are thinking about a blower i'd say go with about 8.5:1 and if you have good forged stuff you can run some pretty good boost. but if i was you id try to get around 10.5:1 if you can and forget the blower, cause when u have good compression you can really hear it (like on my dads car) and it sounds awesome. especially around 6,500 grand! that motor should be awesome when its finished. good luck with w/e u decide to do.

JesasaurusRex

i had 10:1 on my vortec heads im hopeing right around the 12:1 area because the heads are aluminum and probably have a better combustion chamber design. Also theres a lot more duration on this cam than my last. My guess is arch is gonna say right around 12:1...but thanks for ur advice and ya 8.5:1 sounds about what i was thinkin for the blower as well.

69z-28

o yea i forgot about the afr's yea you can get away with a lot more then. that thing will sound awesome at 12.1!lol especially if you are gonna be running up to 7 grand. what are you doing with your 355?

JesasaurusRex

Half of the #5 cylinder wall is missing. Its gone :banghead:

FORCE_FED_Z

There is more to it than just compression and octane. You also have to consider how aggressive your timing is going to be. 12:1 should be no problem on pump gas, you just might not be able to run quite as much timin as you usually would. But as far as possibly gettin blown in the future, thats on you...

But seriously, If the block is strong and the components are strong, there is no reason you can't run 10.5 and also have at least 8 lbs of boost. Thats what I had on my stock LT1 block and components and it made very good power. With different pistons, there is no reason I couldn't have seen closer to 600 rwhp.

JesasaurusRex

How bout 12.5:1 no but i think 12:1 is a nice lil number.

archemedes

I would err on the safer side and go around 11:1 you can be more agressive with timing, and if it gets real hot you won't be hurting

JesasaurusRex

Ya i was researching it a lil more and i think imma go 11:1 with a lil smaller cam. 306 perhaps Maybe even a notch down from that but I love the power band that thing gets especially with a nice single plane intake