As you would imagine with an engine swap, the standard MGB propshaft will no longer fit, and even if it did wouldn’t last long with the extra power. A brand new custom propshaft was made by Dave Mac Propshafts Ltd in Coventry, UK. They are one of the best places to get a custom prop manufactured in UK, and they were also one of the few places who could supply a prop with the correct flanges to bolt direct to the gearbox without an adapter.
The complete specifications for the prop are shown below…
- 1 piece propshaft with 3 bolt gearbox flange, appropriate slider, 4 bolt rear flange with 1140 face, with 1310 UJ’s. It will need to take ~220bhp/200lbft torque on a 1000kg car.
- Front flange
- 96mm PCD 3 bolt gearbox output flange
- 12mm bolt diameter
- 16mm centre spigot diameter
- Rear flange
- 87mm diameter 4 bolt flange (it’s an 1140)
- 5/16” bolt size
- Total length from flange to flange is 1084mm with axle at normal ride height
The longer length of the prop had me a little worried that the it would hit the strengthening section what bridges the transmission tunnel towards the rear of the car. However, it just misses when the axle is at full droop.
The extra length, however, did provide some frustration when fitting. It’s simply too long to fit after the engine & gearbox is in place!
Note, even though the MGB diff has a flange for an 1140 UJ, Dave Mac Props used a special variant of the 1310 UJ on my prop which benefits from the larger physical size of the 1310 but will bolt to a smaller 1140 flange