Oh.. Something to add about the Manley crank is that it uses 2" rod journals. Chevy bearing, more or less... Narrowed with the H. Gives it better rod to block ckearance
I was curious about running a forged 6.4 crank in a 5.7 block and came across several references to using 2.00" rod journals. Seems like it makes the connecting rods much cheaper.
I don't expect I will do anything with my 5.7 beyond the stock crank as I guess they are good for some pretty good HP. But the idea of a forged bottom end makes me curious how to do it so I was looking at ideas. The 6.4 crank adds a little over the stock crank, but pistons are difficult. Probably the easier path is a 6.1 crank and a crank sprocket spacer, assuming the crank tone ring bolting isn't an issue.