Main Bearing help

well this is what they said to get for my block becasue its a 76 so that Why I got them


1/2 groove Magnum/later LA engine:
http://store.summitracing.com/partdetail.asp?part=FEM-4999MA10&autoview=sku

3/4 groove Magnum/later LA engine:
http://store.summitracing.com/partdetail.asp?part=FEM-5095MA&autoview=sku

Off Summit's site, and I verified thru the Federal Mogul online catalog. I never call Summit without knowing the part number i want...lol. It cuts down on the return good authorizations and UPS pickups.