I have an 86 T/A with Tpi 305 but i do not have the owners manual. Does anyone know the recommended fuel octane level for this engine? car is fairly stock (flowmasters, cold air induction) and has over 150,000 miles on it. What type of fuel are you guys using?

 

do a search and u might find out some more info, but u only need 87...for high compression engines the yrecommend 90 or over but stock 87 is fine, a lot of the time i use 89 just to make myself feel better but theres no big difference

 

the factory recommendation for the TPI engines is 91+, but usually 89 is fine. if you're real worried about the possibility of knocking or damage, get half a tank of 89 and half of 93, that evens out to 91 and saves some money you'd otherwise waste on straight 93.

 

i only use 93 but when i have to use 91 i feel alittle power decrese. but then again i am at sea level so i get really good air here. but my engine thrives off 93. mods: intake, exhause, hypertech, cam. higher octane i get the better she purrs.