Can anyone tell me what CR they are currently running safely on 87 octane gas?
It seems most folks are running the 10:25 or 10:50 CR pistons but I would like to use a CR that I can comfortably run 87 octane since that is what most of the marinas sell and is most readily available.

I am planning to run the factory Ka heads at this time with the stainless Fel-Pro marine head gaskets.
I have a set of new L2390F low compression pistons from years ago- Would it make more sense to use these and shave the heads/block a little to get around 9 or 9.5 CR?

Please advise.
Thanks!
Elm