I am building a stroker out of a low deck 400 block. I need a good aftermarket harmonic balancer that can adapt my 4 groove crank pulley and have no alignment issues. My current pulley is from a 73 440 but I was able to ream the bolt holes in order to fit my 69 original 383 balancer. Any recommendations? Mancini sells the pro sport balancers but according to someone I spoke to it will not work.