twinspark

[wesley55]

Do any of you know the highest allowable compression ratio with 92 octane pump gas and 11.3 lift 300 degree cams?

[75evo]

Depends on ignition components and piston cooling. Accurate EFI system may allow up to ummm.... 12:1 with big oil jets and good tuning.

The tuner I've always consulted with says he has built a 3.0 12V with 12:1 compression ROSS pistons, oil jets, S-cams, running on 98 RON fuel (about 92-93 r+m/2 octane).