360 vibration ....help

Thanks for the input. Yes the weight is on balancer.

When I took the cast crank to a local machine shop the guy told me I was crazy for wanting to balance that crank and it wasn't worth it.

I assumed (I shouldn't have) the pistons and Rods would be closer than than stock and wouldn't have to be balanced. Maybe I'll try a converter, if that doesn't work should I tear down the engine , maybe look for steel crank ?

Somebody should slap that guy. Go back and tell that dumbass every single factory Ford 351 Cleveland crank was cast nodular iron. Ask him what the hell does he think they ran in those NASCAR Cleveland engines that spun past 9K RPM and if he thinks they weren't balanced. Find a new machine shop, man.