Inliners International Forums General Discussion Hi Performance spark plug help

Ok I have a chevy 250 12.5:1 compression that was built for alcohol I however and running it on gas . It came to me with autolight ar133r spark plugs I was told these were way to cold what plug should I be running ar135 or 134 or something else? Thank you

I assume it has a stock head. Find out what the stock plug that head uses then go 2 heat ranges colder. Adjust plugs as needed.

Ron

If I recall these engines use an autolite AP26 in a stock build so a colder plug would be an AP25 or 24. At 12.5:1 I would start with AP24's unless your enigne is pre resistor plug in whch case substitute the 2 for a 3 ie, AP36 down to an AP34. Will hunt down my catalogs to double check when I get home.

im going out to buy some plugs today ill let you know how it goes thanks guys