I just rebuilt a 5.7 91 Tpi firebird. After starting the engine for the first few times, I noticed a pretty substantial oil leak. It's coming from around the oil filter. I double checked the pressure sender above the filter, its tight and not leaking. I also double checked the distributor and the plug beneath the heads is plugged. Its definitely from around the filter. I've bought 2 filters already, thinking the first was defective or over tightened. I originally had a 305 tbi motor in it and swapped it out. I do not have a oil cooler installed, but if the oil wasn't even hot yet, I dont think thats the issue? Is there supposed to be a gasket on the oil filter housing(block side)? Its straight metal right now. If so, anyone know a part number?

 

A gasket is not required for a "standard" oil filter adapter/bypass mount. The gasket on the filter should seal the complete area against the milled boss on the block.