[Thumpin455_GTO]

Have a set of JBP ported 670s and either a 455 or a 400 I would like to run them on with pump gas around 89 octane. Last time I ran them on a 400 and pump gas I lost all the upper rod bearings. I want to open the chambers to lower the static CR to run cheap gas and maybe not need 40 degrees total timing for max power.

How far can you go before you find water? Anyone have a template or information with pics of where you can safely remove metal from? right now they are disassembled so nows the time to open the chambers...

I know I could go E85, but that isnt available up here quite yet.. hopefully next year and I can dig out the 13,12, and other set of 670s I been hoarding..