Stumbled on this page and thought it was worth sharing. Interesting note about Jaguar's reluctance to consider the Rover V8 for the XJ40.

https://www.aronline.co.uk/history/features-old-wives-tales/

 

Definitely a good thing, a healthy 4.6 RV8 can barely wheeze out 200hp. An SBC will fit in a 40 just fine.

The real tragedy was that the XK6 and V12 weren’t immediately scrapped for the Daimler Hemi V8.

 

The 2.5 or the 4.5 Daimler V8? The 2.5 in the Mark 2 body made 140 bhp. Probably would have been fun in the SP250/Dart with a 4-speed but was deathly slow in the saloon with a BW autobox. Lovely unit though, loves to rev.

 

Both.

the 2.4 Mk2 is a total dog, the Daimler at least sounded good puffing around.

 

The 4.6 version of the Rover (Buick) V8 was developed for the Range Rover, and was optimised for torque rather than BHP, so to criticise it on BHP is a little harsh.

As for the XJ40 being deliberately engineered not to accept a V8, we will probably never know for sure, but what we do know is that it had to be re-engineered to allow Jaguars own V12 to fit, which would suggest a less than stellar amount of foresight....... (By the time they made the necessary changes, demand for V12s had shrunk to somewhere between 0 and a smaller number!)
In any event, I dont believe the XJ40 would have been any better to own or cheaper to build were it fitted with a Rover V8. The AJ6 engine was smoother and easily as powerful as the Rover, and the bulk of the tooling had been around for ages, so there wasnt a lot of incremental investment required. From memory, at the time when the threat of inter brand pollution would have been at its highest they were struggling to produce enough V8s for their existing demand, so the idea of forcing them into a Jaguar would have had little appeal.
The biggest British Leyland engine debacle, in my opinion, did however involve V8 engines. Inter brand rivalry caused Triumph to persist in developing their own 3.0 litre V8 for the Stag, when both the Daimler (2.5litre) and Rover (3.5 litre) V8s were available. Even ignoring the fatally flawed manufacturing process, a perfectly functioning Stag engine is demonstrably inferior to the Daimler and Rover stablemates on most counts, and was the achilles heel of the Stag, which in many other respects could have been a world class car back in the day. A Greek tragedy for sure.

 

Made little difference, head design was still terrible across all cars it was put in. Even with all the cards pulled out it still wheezes out less than 300hp, case and point the Chimaera 500.

 

But of course it has that in common with most every American V8 up until about 2012!
I’m afraid that if you want to see BHP per litre, you need to visit Germany, Italy and Japan for your engines. Interestingly, all countries defeated in WW2, and whose best engineers had little else to focus on but cars........

 

As a comparison, the best Ford could ever get out of the 5.0/302 was 225hp, so getting 300 out of the smaller Rover engine is pretty good. In the Ford sedans the 302 only ever managed to make it up to 150hp, which is pretty anaemic compared to the power outputs per litre of the Jaguar and Rover engines.