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Discussion Starter · #1 ·
Im looking at a DSS 331 short block assembly with a 10.3 Compression ratio, with an 0.041 gasket and zero deck and 61cc AFR aluminum heads.

Is this too much Compression for 92-93 octane or is it dependant on my cam duration. Im looking at a 224-230 .555/.565 112 Comp XE274HR12 cam.

Any input is appreciated.

Thanks
tim
 

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I think you'll be ok with that cam, actual compression varies a lot with the cam - static compression is just one part in the equation.

That cam has some overlap to bleed off cylinder pressure at low RPM's, and with the aluminum heads, I think you'll be fine. Make sure you start with a conservative timing advance curve and then work up to it so you don't detonate it to death first time out.

I've got iron heads and a smaller cam running 10:1 on 93 octane, and it doesn't have any problems, even with a pretty quick advance curve (36º by 3000 I believe)
 

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I concur, will work fine for ya.
 

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Discussion Starter · #5 ·
Ok then men, she's ordered.

I went with the short block because my engine guy is notorious for taking forever (real busy with dirt track engines). I got alot of good recommendations from this board but to get this thing going this year i had to go crate short block.

DSS had a 331 Pro bullet in stock so it will be here by the end of this week. Came with the Pro-X (lighter) pistons and DSS main Support. I also got the windage tray that bolts on the the main studs. The only thing i didnt like was the compression was higher than i was planning on.

Im glad i ended up going with a separate motor cause the factory 302 will go back together nicely (cheap) with a hone and new bearings, oil pump and timing set. Ill set that in the corner and until i go to sell the car. Then yank the 331 and put the factory 302 back in. Its not the best use (stock 129 hp rebuild) of a standard bore Mexican block tho. Oh well.

Thanks for the help so far. Ill have a million more questions to come.

Tim
 

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I run 89 or 87 octain and runs really great, I have used higher, but don't notice much of a differance at WOT at all.

Maybe a little meaner sounding, maybe a clock would see a differance with 94 octain

Do your tuning with teh low grade, and everything should be great if you decide to use high grade. Never use that additive crap.....
 

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It'll probably be OK, but the cam might be better with 110 rather than 112 center - not much overlap there. Also, recent testing says that AL heads give no extra detonation resistance over iron, so don't count on that. Tune the timing curve as necessary. Our 302 ran good with the old setup - 9.6:1, 204/214 cam, about .055 deck. I had to limit timing to 34 total, but it ran without detonation on 91.
 
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