Cross drilled cranks are wanting compared to a straight shot oiled crank. I put half grooved FM race bearings in my new engine and did not give it a second thought( Scat 4340 crank).
Cross drilled cranks are very old school, the oil has to overcome centrifugal force. I believe there is some sort of a do not take a cross drilled crank past 7500 RPM deal.
But IMO here is the best deal you can do for your Pontiac oiling system and costs you nothing The oil hole in the middle of the main bearing, even the "slot" in FM Race bearings do not.
The shot of oil in you Pontiac block does not come from the middle hole. Where the 3 holes trisect , come together the oil comes from the hole towards the "tab" side of the bearing.
So if you have say a Clevite main bearing the oil shot has to hit the back of the bearing, move over and go on to the crank.
Problem is, your engines rod bearings get starved at high RPM.
So what I do is drill a hole right through the main bearing that lines up with the hole on the slot side. You take a Sharpie and mark the edge of that hole, snap your bearing in and there is enough of a transfer to mark your drill point.
Put the bearing in a vice, wrapped with rags or use copper soft jaw adapters and drill a 1/16" from the back side and work your way up one drill size at a time until it matches the hole in your block. Then take a jewelers half round file and de bur the inside of the bearing.
This is something I have always done. I blueprint my own oil pumps too. The last one I enlarged the low pressure-pickup side and made my own enlarged pickup with a proper cone shaped screened pickup 3/8" off the bottom of the pan.
Engines have great oil pressure. 60 -75 lbs going down the track and the lowest I will see is 45lbs at a fast idle.
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