Do any of you remember an actual paper or whatever gasket between the oil cooler adapter (the piece that the two cooler lines thread into) and the engine block? As I understand it, the "stock" setup (just the adpater that bolts to the block that the filter spins on) does not use any sort of gasket. However, last night, looking up the o-ring for the oil filter adapter for the cooler setup, I noticed that there is also a *gasket* for the adapter listed. It's there on the 4.3 w/oil cooler too, so I doubt it's a mis-print. I'm pretty sure when I installed my setup thats on the truck now there was no gasket in place, but I can't be positive, since I thought the o-ring was all that was necessary. Didn't appear to hurt anything at the time, oil pressure stayed the same, no worse engine problems than before wither. /forums/images/graemlins/smile.gif According to GMpartsdirect.com, neither the gasket nor seal is available, (o-ring was at the dealers less than 3 years ago) although both should be easy to come by/make.