72 340 pass side manifold

Treblig said
There are no dyno numbers for the JGC manifolds (that I have seen). The JGC is 2 1/8" which is as close as you're going to get without spending lots of money. The individual port are pretty good size also. The JGC does not exit in the center like the 623. It exits a little more towards the rear where there is plenty of room/space. You can easily grind out the JGC to more than 2 1/4".

I usually go for performance over originality but that is not the case with my current project so the Jeep option is out. I might consider an earlier 340 manifold if it is similar in appearance but if the asymmetric exhaust size is what the car came with, then that is likely the way I will go.