ok so i am doing a budget build on my 350 i picked up to put in my 87 camaro. i am redoing the bearings but i am running into a problem(i think). my original rod bearings have a oil hole in them. all the parts stores are trying to give me bearings without any oil hole cut into it. is this normal that the oil hole is in some bearings and not others? my crank has oil holes in it where the rod bearings go. but is it necessary for the bearings themselves to have them? it is a gm 3970010 block. here is the bearing that came out of the engine
oh, another question. when putting the bearings in main and rod am i suppose to be putting assembly lube on both sides of the bearings or just the side that touches the crank itself.
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You don't need the hole. Lube only goes on the bearing side.
Quote:
this would be the inside?. leave the outside dry?Originally Posted by Apeiron
You don't need the hole. Lube only goes on the bearing side. 
AlkyIROC
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Jun 5, 2026
The outside of the bearing doesn't spin in the rod. The inside of the bearing spins on the rod journal. The rod journal supplies oil to the bearing. Hole in bearing not required.
Assembly lube to the bearing side that touches the crank.
Assembly lube to the bearing side that touches the crank.
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dont forget to plastigage the mains and all for clearance or mike the crank....
sofakingdom
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There is no oil hole in a rod bearing. No oil goes through the rod, therefore no hole is needed to let it pass through the bearing.
What the hole is, is for a "spit hole" to lube the cylinder walls. Some older engines (about 59 or earlier if memory serves) had this. There was a groove cut in the mating surfaces of the rod and cap, on the side without the tangs (facing the cam), and a hole to expose it was formed by a notch in the ends of the bearing. This provided a little squirt of oil up at the cyl on the opposite bank. At some point, GM decided it wasn't necessary, and quit doing that to rods. But some bearings still have it. Even some large-journal (67-up) bearings have it, although AFAIK no large-journal rods ever got that feature.
Bottom line, it doesn't matter; your engine didn't need it before, and doesn't need it now; and either having it or not will make no difference. Kind of like your appendix... yeah it's in there, but it doesn't do anything any more (if it ever did!) and doesn't matter oif it gets taken out.
What the hole is, is for a "spit hole" to lube the cylinder walls. Some older engines (about 59 or earlier if memory serves) had this. There was a groove cut in the mating surfaces of the rod and cap, on the side without the tangs (facing the cam), and a hole to expose it was formed by a notch in the ends of the bearing. This provided a little squirt of oil up at the cyl on the opposite bank. At some point, GM decided it wasn't necessary, and quit doing that to rods. But some bearings still have it. Even some large-journal (67-up) bearings have it, although AFAIK no large-journal rods ever got that feature.
Bottom line, it doesn't matter; your engine didn't need it before, and doesn't need it now; and either having it or not will make no difference. Kind of like your appendix... yeah it's in there, but it doesn't do anything any more (if it ever did!) and doesn't matter oif it gets taken out.