The 400 main webs are a lot stronger than any stock RB block up
I've broken and seen a lot of RB blocks with cracks in the main webbing, not so in any 400 block, yet luck work
If your going to shoot for the moon later on the 400 build replace the stock main caps with either ductile iron Milidon or some brand of aluminum main caps and good main studs up
Good luck thumbs

Last edited by Cab_Burge; 06/27/17 08:04 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)