Most of the rack mods I like have the steering column shortened to end at the firewall with a u-joint half shaft continuing from there down to the rack input.
Flex link? Got Pictures?
I remember a few years back, Sacramento Mustang was selling a $1000 R&P kit, one of the first commercial designs and it didn't last long. Their system had a "flex shaft" that was used to snake the steering shaft around the exhaust manifold to the rack input. Kinda like an overgrown speedo cable.
The exhaust seems to be a big obstacle in this kind of set-up. I can't see going back to stock maifolds just to have R&P steering. I currently have full length headmans and just holding the steering rack up to the drivers side header looks bad for the home team. I think as far as full length headers go, tri-Ys would be the best to work around. The next best thing (performance wise) would be shorties. Again, this is why I favor the GM rack because it can be mounted way over next to the frame rail and have the center link attached offset (centered in car). Doing it like this (hopefully) lowers the steering shaft angle of approach enough to allow using a half shaft with good quality u-joints on both ends.