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i have a 3200 lb sterndrive boat with a 496 bbc 11.5-1 comp and ned to know what fuel would do the job and be safe.
Av gas straight
av gas and 93 octane pump mixed 50-50
vp 110 mixed with 93 octane pump\
cant afford to run straight race gas due and need your suggestions to keep motor happy
mix avgas and pump 93 gas and put a new set of plugs in and take if for a ride and check the plugs. Adjust A/F ratio as needed.
And don't forget the Marvel!.. :)
i have a 3200 lb sterndrive boat with a 496 bbc 11.5-1 comp and ned to know what fuel would do the job and be safe.
Av gas straight
av gas and 93 octane pump mixed 50-50
vp 110 mixed with 93 octane pump\
cant afford to run straight race gas due and need your suggestions to keep motor happy
Do you have alluminum heads? If so you may be able to get by with 93 octane pump gas and back off the timing a little.
I have a friend that has a 454chevy 12.5 to one compression with roller cam and well ported alluminum chevy heads in a sunkist jetboat that uses av gas. When he got the boat he used only 93 octane and boat ran 6200 rpm's. He ran it that way for a season and finally wiped the original flat tappet cam. The guy he got it from ran it that way originally for three seasons . I suggested that he run av gas for insurance due to compression being so high.
If you have the alluminum heads they dissisapate heat faster than the steel heads and many feel that is equal to dropping a point. Plus boat motors run cooler due to cold lake water running through the block and heads which helps with reducing the detonation factor.
You could start with a mix of avgas and 93 octane and see what your plugs look like plus install a knock monitor for extra safety. Slowly reduce the amount of av gas until you find that you can run just 93 octane safely. You may reduce the timing because the unleaded burns faster than av gas and has more btu's.
My friend runs 36 degrees of timing. and when he runs low on av gas he will fill the boat up at the lake with 93 octane??
Just a thought.
Kojac