I've been comparing gt40 and gt40p heads. I'm pretty much going to grab whichever one I can from my local junkyard, understanding I'll need new headers for the GT40P. I'll probably get the GT40P, because they make more power, but my question is, I know the lower combustion chamber will increase the compression ratio. My question is by how much will it increase. I'm currently running a B 303 cam on stock heads with a few other things, but nothing to increase compression ratio. I'm currently running 87 and would not like to have to run any higher because I graduated college, am currently in grad school, and I'm paying back my undergrad. Does anyone know how much higher the compression ratio becomes when you run GT40P heads, and is it enough to force you to runner a higher octane fuel? Thanks.
GT40P Compression Question
- Thread starter rjpbboi
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You should be just fine on 87 but If you notice any problems it's no big deal to start running 89. (.5) isn't really much of a bump so you'll be fine
If you clean the carbon deposits off the valves, heads and pistons, you might be able to stick with 87 octane.
Carbon deposits can play a roll in detonation, so eliminating them will reduce the likelyhood.
You'd still be on the borderline of 87/89 octane. I have to run 89 in my 5.0 with E7's...but i suspect carbon deposits are to blame. I've already cleaned my GT-40P's I have waiting to go on
Carbon deposits can play a roll in detonation, so eliminating them will reduce the likelyhood.
You'd still be on the borderline of 87/89 octane. I have to run 89 in my 5.0 with E7's...but i suspect carbon deposits are to blame. I've already cleaned my GT-40P's I have waiting to go on
I've got a set of p heads and a gt40 intake in my garage I've never gotten around to putting on anything, depending on where you live I might be willing to sell them to ya pretty darn cheap
