I was ordering a few parts a week or so ago and I always thumb through the paper catalog to see if there is anything else I need. I ran across this Push Rod Cover Gasket GMC-Classic Chevy Truck Parts listing for GMC pushrod cover gaskets. Claims to be correct for GMC 228,236,248,270,302 engines. I'm pretty sure the shorter stroke engines ( 228,236 and 248) use one gasket and the longer stroke 270 & 302 engines use a different gasket. GMC Master Parts Books show GM part # 2135925 for 228 through 248 engines and 2135926 for 270 & 302 engines. Also different part numbers for the pushrod covers.