P76 V8 was 4.4 litres and was a great motor it also had a different bolt pattern on the bell housing to the rover, fitted one into an early pomy Capri that a mate and I use to auto cross and bitumen sprint had a 4spd and a centura diff the only problem we had was water pumps didn't like 6000rpm for to long and were hard to get back then.
Hnmm having built, installed and used these motors in off road racing Range Rovers over the years part of what you have written here is right and part is wrong. Yes the Leyland motor is 4.4 litres and is based on the original Buick 215 ci motor that became Rovers fabled and very reliable 3.5. The 4.4 was a stroked 3.5 and used the same diameter pistons with a longer stroke. Both the 3.5 and the 4.4 motors have the exact same bolt pattern on the rear of the block but the crank bolt pattern is completely different between the two motors. Over the years I've had a number of 3.5 flywheels re-drilled and machined to suit 4.4 cranks.
The 4.4 wasn't a great motor in my humble opinion for a couple of reasons. Firstly the casting process of these motors by Leyland Australia left a shitload to be desired and many of these have pourous and inconsistent alloy around the cylinder liners causing hot spots with some blocks that just cannot be fixed.
Yes back in the day they were a popular choice for engine conversions (stags, hiluxes, boats etc) because of their light weight but you had to get a good one first. An engine rebuild specialist I used to know of in Brisbane will only use these blocks after they have been x-rayed to determine their condition before spending money building a motor. In his words, he disgards 8 out of 10 of these blocks.
The other problem they had was with the re-designed crank that caused the bores to wear oval prematurely (the humble and gutless 3.5 never had these problems).
Their heads were definately better than the Rover heads (although not as good as the Buick 300 versions) as they flowed better so produced better and more power. The local pick was the Leyland Terrier Truck heads as they were the best of the 4.4 motors. I took one of these 4.4 motors out to 5 litres by inserting jag liners and using Holden pistons running a 4 barrel manifold and Holley Projection. That motor was a stump puller but in the end I went with a 350 chev motor and had truckloads more power for a couple of grand. If you wanna rev, get a chev
I know of a local guy here who regularly races a hot street legal P76 and by all accounts it bloody flies so they can be made to perform. But I built, raced and thrashed these motors for a number of years and in my opinion they were never that good ...... particularly without my rose coloured glasses on
Actually I've got one last 4.4 crank in my shed if anyone wants it .. free of course
