The 1940 Ford rearend we are using for this project had already been modified. A 1936 Ford wishbone was bought on eBay for a cheap $85, which normally is not that easy to get for a good price. When it came to the rear crossmember, we had a choice between a So-Cal Speed Shop tubing type with brackets all pre-welded or a 1932 Ford rear crossmember. We had both, but opted for the So-Cal version because it was easier than modifying the 1932 crossmember, and it will give us more space in the rear for an exhaust system.
Just like the frontend, the rearend had to be checked for the correct angle too, as while the pinion angle could be set depending on where the wishbone brackets are welded, the spring mounts to the wishbone ends, and needs to be perpendicular to the ground. We drilled the holes in the back of the center crossmember on each side for the tie-rod bungs. We made sure to drop the frame down on the rubber stops on the rearend to check that nothing else was hitting. With the new rear crossmember in place, the framehorns were removed and the ends of the frame blanked off.
With the chassis now on its wheels, the engine and trans install could be tackled. With such a low-slung framer and minimal ground clearance, the engine would be mounted higher than normal in the frame. This presented further problems, providing minimal foot room in the small 1929 roadster body, so plenty of measurements were taken at this stage. With the engine and trans hanging in the chassis, we measured how high we needed the engine mount brackets to be, and still allow ground clearance for the oil pan. With the front crossmember moved 2 inches forward, we could move the engine 1 inch forward, to get a little extra space by the firewall but still have space in front of the engine. Once the intake manifold angle was checked, as well as the position of the trans mount, we made cardboard templates of the mounts, transferring them to sheetmetal, and welding inside and out, so they could be ground smooth. We decided to use a Vega steering box, but mounted to accept a Pitman arm, not as cross-steering. A modified Vega bracket was used to mount this.
10. Moving ahead slightly, tabs were welded to the wishbones to mount tube shocks, attached at their upper end to modified F-1 Ford truck shock mounts. It's also clear here how the front spring perches mount through the 'bones.
11. Moving to the rear, these simple ¼-inch brackets were fabricated to attach the split '36 'bones to the rearend housing. (We would advise that though the 'bones will now act like ladder bars, they're not really strong enough to be used in this way with an open driveline, and suggest adding upper links or a torque arm, too. –Ed.)
12. Everything was mocked up and checked for measurements before anything was tacked in place. We ensured the rearend was straight and central in the chassis and with the required pinion angle. In our case it was 2-3 degrees negative.
13. The rearend brackets were welded a little at a time, to prevent excessive heat buildup, and hence warping of the rearend housing.
14. Roy Fjastad Jr. at West Coast Street Rods tack welded the rear crossmember after it was checked for position and angle.
15. The rear spring is actually a front spring from a '40 Ford, which will give the roadster a softer ride than if we used a Model A rear spring. The rear crossmember from So-Cal Speed Shop will give us more space in the rear for an exhaust system.
16. Gussets were welded at each end of the rear crossmember. These pre-fabricated gussets are available from metal supply houses in different sizes.
17. The split '36 rear wishbone also mounts using tapered weld bungs in the ends, but machined to accept bigger ¼-inch tie-rod ends, the bungs welded into the center crossmember.
18. Engine mount towers were made in cardboard first, to determine the shape and position, then the template transferred to steel plate.
19. Fjastad Jr. fabricated the towers, welding them inside and out so they could be ground down to a smooth finish with no loss of strength.