I am still collecting parts for my 40 ford coupe. Why do so many people split the wishbones? Is there a benefit? I plan to use a BBC and a th400 or a 4-speed(i have not decided yet). My dad had a 40 coupe when I was a kid. He said the bones were split but he does not know why? I assume when a modern transmission is use the mount for the bones is changed. Can anyone enlighten me?
Most methods of fitting a modern transmission will force the removal of the portion of the stock frame that the wishbone ball seats in. Also there is likely interference between the wishbones and a transmission fluid pan. Many of the better mounting kits split the bones just a bit to move them out of the way. I can't think of any reason to split them all of the way to the outer frame rails.
Mostly because there's so little room in the x-member section for anything but the stock tranny in the stock location. As soon as you introduce any transmission larger than the stocker...you have to start removing metal, and because the pivot point for the 'wishbone' is right there at the center of things, ya gotta swing 'em out to the side so you can modify that center section of the X to make room. Crawl under a 39-40 with an OHV and an A/T at a car show and you'll see what I mean. dj
i believe they split them to gain clearance for engines and transmissions personally i think it actually degrades the driving and handling . i have a 40 that i put a 351 4 speed in and i had to remove the original x from the frame but when i redid it i still incorporated the original center pivot . when you split the wishbone as a tire encounters a bump or incline it will actually cause the axle to twist . now if you use a 4 link system you don't have the twisting issue because the 4 link has rotating bushings on both ends whereas the wishbone is mounted rigidly to the axle . i have a tip if you are going to a dropped axle . get a 1935 or older style and shorten the 40 spring , it will give you a much better turning radius thats what i did on my 40 .
Having built many 35-40 Fords, and components for them, the reason to split the bones if to provide for trans clearance and to facilitate the removal of the trans should it need repair. The kit we make, and most others as well, mounts the bones as close to the original point as is practical. DO NOT USE A FOUR LINK. These reduce the turning radius and have many other problems too numerous to list here. The 37-40 axle is the narrowest one that Ford ever built, so going to the earlier one only make for a shorter spring. I have a split wishbone/dropped axle under my 40 with over 130K on it with out any problems. One issue you will have is with the trans. The TH 400 or 700R4 will require the center to be opened up substantially to get it in. We do build a widened X-member kit that works very well and can be used with a split wishbone.
It will also give better handling according to an old 60's roundy round racer i know, he has a couple fat fendered stockers that he has split the bones on, guess it takes some of the side to side sway out like a sway bar would one thing to remember though, it will KILL your turning radius if you dont v-cut and kick them in
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