Compression ratio 4.6

[Xj01]

Does any one out there have a stroked 4.0 with high compression? Looking into this 4.6 build and I don't mind running high octane gas? Any thoughts?

[RenoF250]

It seems many here do. I am going for 87 octane myself. It seems the general consensus is a DCR of 8.5 is max on pump gas. At that level you also need a 0.040-0.050" quench height and everything smooth in the chamber and a good cooling system.

[FlyinRyan]

It seems many here do. I am going for 87 octane myself. It seems the general consensus is a DCR of 8.5 is max on pump gas. At that level you also need a 0.040-0.050" quench height and everything smooth in the chamber and a good cooling system.

I would caution you about running 87 octane. Even with a proper calibration, the gas quality in your locale is quite poor, even on 91. I've had major issues trying to use any real amount of timing lead on winter blend gas this year, Cali and elsewhere.

No issues running high compression, provided the proper plugs are used.

[Wombat Ranger]

I am at 9.6:1 static and around 8.1:1ish Dynamic. I run 87 octane. I drive it like a hot rod because it is one now. But I don't rev it out much because there's no more power at 4 1/2 grand than there is at 2. Only do I get any ping when I am approaching 5 grand at full throttle. So I just don't do that. I have yet to try any better fuel. Oh and my quench is all wrong at around .091". Runs smooth and strong though.

[cal]

I'm like 11.5:1, running on 100 in competition and a 50/50 blend of 100 and 91 when we're just playing.

I could probably go lower, its never given a hint of detonation..