B18b1 block w/ b1 crank. C1 head. Getting low comp pistons but i dont know if I need to get Different length rods to match the gsr head.

 

You got to match the rods and crank together ls rods to ls crank or gsr rods to gsr crank no mix match.

 

i know the gsr rod lengths are at 5.430 and b1 rods are at 5.394. Would it be ok to run 5.394 rods with a GSR head?

 

You ll be fine with that setup depending what pistons you use.

I ran a ls crank, ls rods with Usdm type r pistons in a gsr block with gsr head and had no clearance issue at all. I would put my compression at around 11.2-11.5cp with the head milling too.

any higher than that I wouldn’t risk unless you building a track car and using meth kit.