Here’s a quick bit of info on how we matched the rack to our 62-1/2″ Mustang II crossmember.
Theoretically, you could widen a Mustang II crossmember as much as you wanted… the key is protecting the control arm pivot points and tie rod geometry. When you’re thinking of widening a Mustang II rack, there are two ways to do it properly… outside the bushings and inside the bushings.
‘Outside the bushings’ refers to pushing the tie rod ball and socket joint towards the wheel. This has to be done the same amount as the crossmember is wider than stock – typically 2″ per side on a 4″ wider than stock configuration. Longer tie rod ends can also be used on a 58″ wide crossmember.
‘Inside the bushings’ refers to lengthening the actual rack and rack housing. For a much wider crossmember, this might be a good option… there are even racks available that are wider than stock for this purpose. Your crossmember will have to be set up or modified for a wider rack. Welder Series crossmembers are designed to use rack extenders – the ‘outside the bushing’ method.
On my 1968 D100 truck build, I used a Welder Series 62-1/2″ track width crossmember, with rack extenders from Heidts. I used two (4″ total) on the passenger side, and one (2″ total) on the driver side. Our rack mounts favor the driver side, so the steering input shaft is closer to the frame rail and will be more likely to be aimed away from your headers.
Note: the rack bushings mount with the shoulder against the crossmember, and the serrations biting in to the rack mounts. Use a bolt size washer (included in our #24410 power rack mounting kit) on the front of the bushing, and let the bushing mushroom as you tighten the nut.