Bill, I don't have the engine running yet. It's a 355 Gen 1 SBC @ 10.5 to 1 CR and 6-7000 rpm valve train parts. I do know of a race gas 347, something in excess of 12 to 1 CR, being started for some time with one of these. The real question in how long you can crank a big high CR motor with really stiff valve springs before the battery can't hack it any longer. I think that one of these 925's will be fine with just about any 400 CI ish pump gas motor as long as the motor is tuned correctly and SHOULD start. You can crank ANY battery dead if you try hard enough I suppose.
I really like these. They are clean, dry, fairly priced, light, small, and pack a lot of power.
Molleur, You guys don't miss anything. Ya, I'm getting closer everyday.