Wow they do cost a lot more. Ya battery power was my first thought to.
I tested at the starter and had 12.51v so i thought maybe if i run a another battery parallel ill have more power. So i pulled the batttery out of my truck for a combined total of 12.80v at the starter and 1600 cold cranking amps and it still will not turn it over.
Only way it will turn over is if i ran jumper cables from my truck and have it running then it will turn it over.
Of the mods ive done to the motor the only ones that would effect compression are im running .010 head gaskets, precision cams cheetah grind, and gapless top compression rings. I havent put a compression gauge on it yet.