Thanks Tom and Chris,
I was leaning to the 3/4 groove but i read in a chrysler builders book that they suggest full groove. I am with tom i don't like the fact that i am going to loose aproximently 1/4 of my load bearing surface with a full groove bearing. But i do understand the importance of feeding those large rod journals with plenty of oil. So i was thinking the 3/4 would be a "best of both worlds" situtation..