Thanks for the quick replies. I'll gather up bad screws and the pushrod with separated cup/tube and take pictures. The the bad screws were all on the exhaust valve rockers. The Maker of the pushrods is unknown. I'll measure the key dimensions more accurately.
My 40 Chevy has been running with the GMC engine for 24 years, but only going 1,000 miles per year along with a drag race or 2 anually. So, I can't complain too much about the engine. I don't have a record of the type of the pushrod maker or size. It is tubular with a ball on one end and a cup on the other. I'll measure the key dimensions.
My valve train consists of an Isky E2 (.298/.448 cam/valve lift, 264/228 deg duration, .018 lash) cam, mushroom solid lifters, tubular pushrods, GMC fabricated rocker arms, 1.94/1.60 In/Ex Valves, 470 # springs.
One thing I wonder about is the length of the pushrods. It looks like the adjusting screws are way down in the rocker arm threaded socket leaving only a few threads above the lock nuts. Seems like the pushrods may be too short by 1/8 inch or so. I compared them with the stock pushrods and they are identical in length.
