[unruhjonny]

I am trying to positively ID a set of manifolds that I have here as repops vs originals.

I believe that this is a matched set from a 1968 GTO (hence the location of the post).

I was wondering if anyone has pictures of the casting numbers of these;

I understand that the drivers side 9791637 is a 1968/1969 casting number, while the passenger side 9777642 is a 1967/1968 casting number (often mistakenly assumed to be a '641 casting number - but that's the part number of the assembly with the HRV).

The passenger side manifold has the HRV plugged and removed.

Thanks in advance for considering helping me with this little task

[1oldgoat]

Here are a couple of pictures of an NOS set of 68 Ram Air I manifolds.

[unruhjonny]

Thank you very much.

I was trying to establish if what I have here are originals versus reproductions of some sort;
I had guessed that the drivers side was OEM - but the absence of a casting date had me wondering;
I had also guessed based on the provisions for the heat riser valve that the passenger one was OEM, but between the oversized casting number, a non-conventional casting number suffix, and the absence of a date code, I was wondering...

Your drivers side one looks like a dead ringer for mine, but my passenger side one has the casting number in a different size and location than yours...

Would anyone care to chime in?

[1oldgoat]

I'm sure yours are originals as they have never made a reproduction that was machined for heat-riser valve. The difference in size and location is likely due to different batch runs. I have numerous cylinder heads with different fonts, sizes and locations of casting numbers for the same heads. I have 1968 model 31's with two totally different size and locations of the numbers. One has both the 3 and 1 on the same exhaust runner and the other set has the traditional layout with the 3 on one runner and the 1 on the other. Just my opinion.

[unruhjonny]

Thank you VERY much for your help in this matter.

[1oldgoat]

Happy to help.