Castlemaine Rod Shop used to be owned by Rod Hadfield...a well known and respected car builder. He was the driving force of this shop for several decades that I know of before he sold the business. The P76 is virtually the same block with some significant differences...taller block. The rear of the block is the same but the crank flange is different.
I run a Range Rover gear reduction starter on my P76 engined P5. It is a tiny unit in comparison to the original P76 or Rover unit. The only mod to fit the starter is to place a 2mm spacer plate between the starter and the housing it bolts to on the block. Given this there would be minimal difference in fitting the components listed. I still use the original dished BW35 drive plate. Other P76 owners sometimes adapt the flat Rover Drive plate. There are several P5Bs over here running the P76 engine with the original P5B gearbox. If it were me, I would get the P76 Kit from Nik Demopoulos (ref to links)
Looking at the pictures in the link it is easy to see the dished P76 drive plate. Simply use your Rover flat drive plate and fit a spacer between it and the crankshaft flange.
If you're serious about doing this, remember nothing is completely bolt up. You'll still need to modify the tailshaft (length & flanges), adapt the trans shifter and recalibrate the speedy to mention just a few things.
I reckon the kit is a good deal and cheap for what you attempting to do. ~ Vince
Im about to fit a LT77 manual gearbox to my P5B saloon.I agree that the P5B is one of the better autos of the period,but I hate autos.Love the car but either the auto or the car goes.LT77s getting a bit rarer now,esp. two wheel drive versions.Will go LT77 for now as I have a good box to hand.Has anybody fitted an R380(later version of LT77)to a P5B?
Picked up a Triumph TR7 with a Grinnall V8 conversion on fleabay. Somebody thought enough of their TR7 in 1990 to spend £10,000 converting it to a Grinnall V8. When I bought it ,it was usefuly filling a hole in a hedge. Hey presto,rebuilt LT77 gearbox complete with bell housing,coupling and gearchange,flywheel,as new clutch. Engine full of soil but ring gear as new.Good master & slave cylinder.Cover is off P5B ready to drop the BW35 out. Looks as if the TR clutch pedal and mount will fit with a bit of fabrication. Even with .77 5th gear the P5B will have a lower ratio than the SD1.
Got the LT77 box in the P5B.No mods needed to the car,but tricky bit of fabrication for rear gearbox mount(using the origional mounting rubber).Front propshaft extended by 37mm.Remote gearshift comes in same place as auto selector lever.Cut brake pedeal to fit Disco pedal rubbers(Nice big R on them).Engine not moved so looks origional under the bonnet.Only problem was clearance between clutch slave cylinder and crossmember.Ground clearance off the cylinder and raised rear of gearbox 15mm.Heavily modded TR7 clutch pedal.Just got to see if it works now.Fingers crossed. Note, after road test.Transformed the car.Much quicker through the gears and more relaxed cruising.Pity Rover never had this gear box available.
I know the purists will condemn me, but I've got a manual BMW 325i waiting to give up it's drive train for my P5 saloon. The P5 was very unloved and requires a lot of work, so I don't feel too bad about modifying it.