J-car rack and pinion

check this out

http://www.1969stang.com/articles/rack.html
Its not for a 71 conv. but it is still a relevant link.

As for the cross member, on any car really, why does the cross support have to be touched? If anything a stronger unit should be installed and the rack can be mounted seperately altogether. I wish my car had a brace that size, mine only has a little tube with a bolt on each end and it does not tie into the lower arm mounts like the fairlane picture does.

That is the point I was trying to make earlier, the J-rack can be mounted off center with a spacer between it and the center link, like in the trinitymustang link or the TCP setup. It really is a challenge to lay under the car, hold up the rack and decide where to start.

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.

o.k. looking at the picture of the steering shaft linkage see how the original steering extends out of the firewall a few inches? If that is shortened back to the firewall, it will lessen the angle that the half shaft u-joints operate in. I remember reading about the maximum angle that you don't wanna exceed on those joints, but I can't remember the specifics. I'll see if I can find a picture of a shortened steering shaft.

Re: the 71-73 Mustang Saginaw box. I sent a box to AGR Steering to be reworked two years ago and they were able to rebuild it with 12:1 ratio, high-effort components that matched the WS6 TransAm/Z28 internals. Cost was about $400, IIRC. Car was amazingly transformed.

A word of caution on the flex shafts. If they are run too close to extreme heat (headers) they can fail. I haven't seen one break but have heard that the laminant or coating that holds the cables together breaks down after many heat cycles. The breakage usually occurs during high stress, such as turning the wheels with the car stopped or during a three point turn.

On the rack options, due to the narrow centerlink mount of the J-rack and other center take-off OEM racks, it is necessary to extend or reposition the centerlink. This leaves the door open for deflection. You will always have off axis forces because the tie-rod is not perfectly inline with centerlink. It would be interesting to see if there is a measurable amount of deflection in the long end of the centerlink or the wrap around mounted centerlink. This flexing will have some effect on the responsiveness of the steering and may also end up with some fatigue issues after extended use. I have only seen one aftermarket design using an OEM rack that has addressed this issue by adding a support to the long end of the centerlink. Without actually seeing this unit in person I cannot fairly comment on the strength or ridgidity of the support. But at a glance it appears to the be one of the better bandaids when using an OEM rack.