[455HOGT37]

So here’s the story:

I have a long term 63 Cat project that has changed directions over the years and is now the benefactor of many left over parts thanks to a thinning of my collection. What was going to be a minimalist bracket car with an automatic, it’s now a 455/M-20 street car. The one legger, freeway geared original rear will not do. I could certainly swap out the pumpkin and axles with something more suitable to the 4 speed, but That’s expensive. It also happens that I have a nearly new Currie 9 inch that I had built for my 68 ElCo laying dormant in my shop. The 9 inch was damn expensive, but it’s everything I could want for the Cat: 3.50 gears, traction lock, 31 spline forged axles and essentially brand new. Unlike the Pontiac rear, it has a massive aftermarket following for things like brakes and stuff. The one problem is that as it’s built for the A body, it won’t bolt in. But it is “close” in the sense that it’s a 4 link, coil spring configuration. So just how much work will it be to get it to fit? I’m about to find out.

With an afternoons work, I was able to drop out the 9.3 and stuff the 9 inch in there to evaluate the changes. It looks like it will work with some fabrication. It’s now a roller, but a ways from capable of driving. So far, I’m in for the following changes:

New lower control arms. The Cat arms work for the time being, but the angles are not quite right. New arms will have the bushings offset slightly to accommodate the slightly different width. On the plus side - the A body rear sway bar will fit
New upper arms. This is a more severe change from the Cat parts. The point where the A body arms intersect the frame is MUCH narrower than the Cat brackets. Fortunately, it will be fairly easy to add new brackets to the frame in the correct place. I don’t even have to remove the old.
New spring perch. I hoped to not modify the Ford rear, but I’m planning on airbags for springs so there will need to be a simple welded on perch. There is a chance I can get clever and fabricate a bolt on perch - we’ll see.

Anyway, I’m not attempting to convince anyone that they should modify their Cat to use an A body rear, but for me the juice is worth the squeeze. I’ll post progress as it comes (slowly) Hope some of you can get something out of it.