3.750 6.000 or longer(rods), Internal balanced, 2.100 rod journals, 2.450 main journals, 1 pc main seal. so will it???

 

Yes, you will need to do final balancing and clearancing on the block but it will work, just take the whole recip assem (including rings, balancer and flex/flywheel) to the machine shop and have them balance it, they will probably have to add a little weight but it will be woth it for parts compatability.