Hi,
I don't have the original exhaust manifolds but I do have a 71' Cuda that I cloned to a Hemi with TTI headers. I just got it done after 7 years and now after rebuilding the (new) engine twice, yes twice because my 1st attempt to run the engine with a BRAND New HYDRAULIC COMP CAM was a disaster, (13 lifters were ground , that's no lie) It was said that I didn't have the ZDDP additive when I broken in the engine that caused the cam to be grounded. I called 2 of my friends who are the machinist at 2 different speed said that even with the additives they had big problems with COMPS CAM. Just some helpful info if you are thinking of changing your cam. Well as far as your exhaust manifolds, you should be able to get the bolts from the underside of the car. I was surprised how easy it was to remove my headers. Again, I do not have or own stock manifolds but I think it should be the same as the headers. I hope this helps. Just curious, would you send me some pics of your car? Thanks and good luck. tyron
P.S. If you have any other questions please feel free to email me.