I'm planning on rebuilding the SO 5.0 engine in my 87 tbird to the HO varity. Depending on which combination of parts the compression ratio can vary from 8.7 to 12.0. I want to continue using the 87 octane pump gas but while I'm asking I might as well ask for the other octanes.
If you please would answer, What is the max compression ratio the 5.0 HO engine can take that won't cause pinging/detionation using the 87, 89, and 92 octane gasoline? Also does engine cubic inchs make a difference? Was considering stroking the engine.
I'd say 10:1 is safe bet on 92 any more u can be pushin it... and altitude will have some bearing on it. dont think cubic inches gonna make much of ad ifference... u can get octane booster tho... and play with timing... but there is pro's and con's to playin with timing which i do not know but someone else will.
Cubic inches only really matter in that the bigger the engine, the more power you can make on lower compression. I.e. a big block can make 400 hp on 9:1 easy, whereas with a small block that would be harder to do.
I want to stay with 87 octane because this is a daily ride. Sure don't want to be adding octane boost. That would send me to the poor house.
On 87, my guess would be that you probably wouldn't want to run more than about 9.5:1.
9.5 is good. Glad I found out before buying the wrong heads with smaller cc.