I'm using 440 source's off brand fluid damper.
The crank is the one part that I'm not really worried about. I think that piece can handle a lot more power than what my engine is throwing at it.
I think u will help it w/ a girdle. I run a 440 source fluid damper and like it. I think it`s about impossible to totally stop cap walk. My approx. 600 horse sbc 406 had splayed 4 bolt mains and it had as bad a capwalk as I`ve seen. By comparison, the s.s. type hemi we used to run didn`t have hardly any, but still had a small amount. A girdle will definitely help a r/ b in my opinion.