currently working on an lq4/t56 swap im doing in a nissan 240sx and i just got the motor running a few days ago. while trying to bleed the cooling system i noticed alot of oil smoke coming from the passenger side header. upon further inspection, it seems as though engine oil is blowing right out of the side of the head/block mating surface and onto the headers. obviously i assume this means the head gasket is no good. the motor is an 03 LQ4 with and ls1 intake and long tubes. I want to do this right the first time, so i id like to know what part numbers to use for new gaskets, and if its worth it to have the heads gone through at a shop, or should i just straight edge them and clean and replace. i know the head bolts are tty so i will be replacing those. also what would be the proper way to prep the 2 surfaces once again without having to send the block and heads to a machine shop.

 

Are you sure it's coming from the head gasket? Only coolant goes through the head, oil travels through the pushrods and drains into the pan so it doesn't have any pressure at the head. Most likely it is coming from the valve cover, you should clean off that side really well then see if you can tell where it's leaking from, if it's hard to see you can sprinkle some baby powder on it and see where it's starting from.