I'm trying to nut out my options for a center cross member in my AV8 chassis. I've read Bishop/Tardell book a few times, but a few things on my car are different. I'm running a flathead and Lasalle box in an A model chassis, 39 front and rear end. If I were to use a 32 k-frame with the Lasalle box I will have to set it back a few more inches. Then the pedals and wishbone mount will be moved back with it. The pedals would be easy to fix, but the wishbones I'm unsure of. Does anyone know how much longer a Lasalle box with the ford torque tube conversion is? Will the longer wishbones from a 36-39 ford help out at all?
My 2 cents.... I wouldn't worry too much about the wishbones. I would just put the trans crossmember where it needed to be to get your engine in the correct spot with respect to the firewall and radiator, and let the wishbone mount end up where it ends up. Wishbones can be shortened or lengthened quite easily even when running an unsplit bone. The chances of a later wishbone being the right length is unlikely, and the later bones didn't have the "U" shape to them near the rear mount to provide the clearance to the engine/trans like the earlier ones (A-'34) did. So if you're going to run unsplit bones, your best off getting an A-'34 wishbone and customizing its length.
Depends on how you set up your lasalle tranny. If you spend the money to have the main shaft shortened you can run a K-member and can get a tardel repop off eBay. If your gonna run the tranny without the machine work done you might as well make your x member and you will have to run an open driveline.
I am going to shorten the LaSalle. I was hoping not to have to weld the wishbone. We need engineers reports here in Australia, and they look poorly on welded suspension parts. Will the later wishbones not clear the gearbox at all? If I'm going to have to cut and weld them I might have to splice the ends of an A model one to the longer 39 ones.
Tyson You'll have to set the motor and trans in place, then build an x-member to suit, then worry about the wishbone length and pivot configuration. If the wishbone is suitably re-inforced and you have pictures of it, I'm sure your engineer will approve it. 4 bars and hairpins are welded and engineers accept them
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