Correct Factory Exhaust Manifolds 70 GMC K2500

[BILT4ME]

I am looking for the CORRECT part numbers for both exhaust manifolds for a 1970 GMC K2500 3/4T 4x4, with a 350 and 4sp.

Both manifolds that are on this truck are broken and I am quite sure they have been replaced multiple times due to the VERY poor care that was taken of it. It was used in a construction business and was flat-out abused.

I am looking to start out as if I am going to restore to correct factory specification, then my wallet will help me decide from there.

I have searched this forum as well as many others and I cannot seem to locate the correct literature that I KNOW is out there.

I am looking for the CORRECT casting numbers for both left and right.

The CURRENT ones I have are:
3747038 (Left)
3932465 (right)

I believe the right one to be correct, but not the left one. Please help.