Howza Bruthas, As i fell my way through the darkness and reach for light with this crazy roadster project for the Boy, I actually feel like I am gaining ground. My questions for everyone are- 1-is there a formula for the rear trailing arms/wishbones when mounting them directly to the frame? 2-is there an angle the front axle needs to be when mounting a spring in front set up suicide style? 3-What motor mounts work well with small block Fords for one of these crazy projects? 4-Radiator mounts? I am using a Model A grille. Thanx all........
There is no formula, no mathematical one at least, that I've ever heard of for mounting rear wishbones. Just be careful to use tire-rod ends on them, try to use an additional torque arm somewhere in the system, and use a panhard rod if you're subbing coils in for an original style buggy spring. Look at lots of pictures. The front axle needs to have about 4-6 degrees positive camber however and wherever it's mounted. There are any number of Ford small block motor mts. made for use in Model A ch***is. No reason they shouldn't work in other applications with minimal modification. Try Ch***is Engineering or Speedway Motors. Be aware that a simple dropped tube transmission crossmember may seriously obstruct under floor mounting of a power booster equipped master cylinder. Aftermarket radiators meant for Model As should have mouniting brackets appropriate to the intended use. Recoring and modifying an original is an option for relatively low horsepower applications. Above the 150HP level it gets a bit dicey. Search Mustang radiators on the board for info on this inexpensive alternative.
Thanx Darwin. One more question, what about crossmembers? Should an A frame be X'ed? I really want to do this right. Thanx all....
A split wishbone for the rear is a really sketchy way to go. Even with an additional torque arm to keep acceleration forces from breaking them, the stresses from the axle not being able to pivot under the car will eventually break something. I'f your dead set on doing it that way I would just say that longer is better to give more room to flex the bones. I built a four link using exposed split '36 bones as the lower links on my A.
Just going thru a lot of this stuff myself. definitely put a X or K member in that frame. The split rear bones aren't a great way to go. Tman did a good post on a three link system. Search it out. There are quite a few posts on here that discuss rear axle locating ideas. Good luck Pete
As for bones in the back I am using the Model A units and they extend all of the way up to about mid body. Is that long enough?
Here's a pic of my model A...those used to be solid mounted split bones. They worked without a problem for about 7 years and probobly 50K miles. But eventually cracked one of the 3/8" brackets on the axle housing when I parked on a real uneven surface at the beach. Now its a four link (I think it was a four link when the picture was taken).
I agree with Darwin. The books here state 7 degrees. So i'm not sure on that. Somebody else might be able to clarifie. The main thing with the diff set up is to get the pinion angle right
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