jay d - No idea that I can figure out.
After going back and looking at the
O'Reilly's multiple offerings, even though it says its listed to fit your 270, a closer look at their full application lists for each of the products shows they supposedly fit engines that have no relationship to the GMC inline 6. Listings included fitting GMC V-6s, Chevy 261s, Chevy V-8's and so on.
None of the products pictures match the design of the 270 oil pan gasket either. I seriously doubt that what they offer is worth chasing your tail on.
