As for chebby lifters and pushrods.... just buy olds..
Not good advice! Just because something fits doesn't mean it's right.
Chevy's are all .842". Fords are .875" Olds/Pontiac are .842" also but the oil band is in a different location compared to a Chevy. Now you could use
a Chevy lifter in a Pontiac/Olds as long as the cam was not over .475" lift. Anymore and it will starve the engine for oil. Your safest bet is to buy the retro hydraulic rollers. $600 is not bad, I know first hand how much money it cost to do a short run of these.