Welcome to the board, there is a lot of controversary about main girdle use on Mopar BB Wedge motors do to the perceptions and myths spread by the manufactuers, vendors and some users on here I've seen at least three or maybe one or two more RB and 383 B motors crack the main webbing between the bottom of the cylinder walls into the main webbing, a girdle can't and will not fix that I made a race gas stock 440 block 526 C.I.stroker motor using ductile iron main caps that made 845 HP on a DTS engine dyno in Klamath Falls OR at 4300 Ft altitude in the spring several years back. I used that motor as a dyno mule and sold it to a freind and customer who has not raced that motor yet due to going trough some rough family probelms and then changing living up here to moving to Lake Havasu and that new track not opening yet down there My message is don't waste your time and money on a girdle, put it towards a lot better race block with 4 bolt main caps already cast and machined into it On your deal I would buy and have either Ductile iron or aluminum main caps and ARP main studs installed and align hone for your block I do that on all the stock Mopar BB wedge blocks I build now, I do try to build 400 blocks instead of the 440 blocks now though for anything at or above the pwoer level your shooting for All the stock 400 block main webs are a lot thicker than any of the production 413, 426 W or 440 blocks where Good luck on your build