72'z'steve
Veteran Member
Didn't the "factory" 4 bolt main big blocks have the 2 threaded bosses ports down by the oil filter for external oil cooler? I know my old ls-6 chevelle had them-that was a tell tale like the "dimples" on the ends of the rec port heads.Did the 396/402 4 bolts had them also? just a thought Later Steve!!