Interesting topic here. I'm building something similiar. I have a scat 4" crank with the stage 1 lightening. Weighs in at about 53 lbs. Bobweight with the HEAVY scat H beam rods comes in at 1903 grams. Wiseco protru pistons. Heads are Edelbrock LA style with 5/16" stemmed 2.080/1.600 valves. Intake's flowing about 315 so far. Might see more but not at a lift that's worthwhile. Super victor intake, heads will be ported to a W5 port window. Compression'll be about 11.5:1. Planning on a solid roller cam with the LS1 firing order but money is an issue if I want to see this thing run in the next 5 years. T&D rockers will be a must for the RPM I expect this thing to turn. Engine should be set back so I can run the Canton rear sump road race pan and a T56 will back it up.
As to the reason why the crank companies won't change to chevy journals, it costs money to change things. The pencil pushing pansies that be don't like to spend money if they can't see the returns immediately.


As a side note, I ran a 408 with Eagle I beam rods that the bobweight came in at about 1840. Same pistons.