I just picked up a 78 nova with a 383 stroker 13.2 compression it runs on av gas how can I run this just on 91 octane pump gas with out a stall knock
03-15-2013 05:56 PM
Replace the pistons.
03-15-2013 06:07 PM
can I just retard the timming
03-15-2013 06:12 PM
Not with that much compression. You need pistons with big soup bowl dish tops to run 91 octane.
03-15-2013 06:19 PM
I hope there is another way to do this I dont want to tear the engine down for this will it hurt to put octane booster in the 91 octane I picked the car up for 2k thinking it just needs a good pait job not pistons to run it cheaper haha
03-15-2013 07:12 PM
If it truely has 13.2 to1 thats even too high for 100LL blue AV gas in my opinion. That is the most common type of AV gas you're likely to find. What heads do you have on it? If you have 64 cc chambers you could drop it some by swapping to 76 cc chamber heads but still likey to be on the high side for 91 octane would be my guess without doing the math. There just is no way to do what you want without swapping parts.
You need to know exactly what you have to make a wise plan of action.
03-15-2013 08:19 PM
thanks ill have to look at the build sheets I did not build this engine myself but was given the papers and receipts for the car ill check them out and post what I have for suggestions thanks for your time guys
03-15-2013 08:34 PM
yep heads are 220s with 64cc chambers
03-16-2013 04:58 AM
X2 on the water meth injection
03-16-2013 12:08 PM
Swapping to 76 cc chamber heads is only going to drop you to about 11.25 to 1. 72 cc chamber heads will put you in the 11.8 to 11.9 range. Neither is low enough 91 octane for me, however it would run nicely on 100LL. Actual compression may vary depending on if the block was decked and what head gaskets were used. Your not going to know what deck clearence is without disassembly. Sounds like you have some nice heads that you would want to give up anyway. Running Av gas on the street is tax evasion just like running off road diesel. Not making any judgement here just don't take this as an endorsement.