[cicero819]

Greg, you're right we kept it a secret until you've just let the cat out of the bag.Ok, here we go, all 305 truck engine in 3/4 ton and 1 ton 4x4 application had the four bolts main, all 1/2 ton had the automotive 2 bolt main but due to sometimes delivery problem from the foundry the auto version was install in 3/4 and 1 ton.This confirmation from my neighbor who was a GM tech in charge of formation for their technicians.U.S. Canada and Mexico.cr