highest compression on 100 octane?

[bdrue]

i have a 400 ex, lookin at a hotcam stage 3. how much compression can you use with 100 octane? looking for a stock bore piston (for now) who sells the highest comp piston for a stock bore. And will there be any connecting rod/head gasket problems? i think i saw je had a 12 or 12.5:1 piston for a stock bore...

first off, why the heck would you want to use stage 3 cam with a stock bore?

and with a timing advance I can run no lower than 100 with 10.8:1. but that timing advance will get ya every time.

[400exrider707]

A stage 3 will go find with 12:1 compression. At about 12:1 you could probably use 100 octane, but generally at that compression head studs and heavy duty rods become a good idea. Not a necessity but an engine is only as reliable as you build it.