My first car was a Triumph 1500TC, the forerunner of the Dolomite. I really wanted a Stag though when I was 18.
The 1500 TC was a similar set up as used in the upgraded 1500 Spitfire, that also had TC’s.
They also did a 1500 FWD model version.
It was a bored out version of the original 1200cc Herald engine really.
Increasing the power came at a cost thought, because they suffered from crankshaft rattle as a consequence.
The Dolomite came in a 1750cc format and the 2000cc Sprint.
Effectively it used a Stag engine cut in half

.
As a result, it suffered from the same similar problems of overheating, that the V8 Stag was plagued with.
The Triumph attempt at producing a V8 for the Stag was hopeless.
The best V8 unit that Leyland cars used, was the one fitted in the V8 3.5 Rover / Range Rover / SD1 V8 / MGB GT V8 ( detuned ) and the tank of the 3.5 Coupe’.
Loverly, smooth, reliable engine, made by Buick if I recall.
Set up correctly, you could stand a cup of water on the engine when it was running and it would just sit there balanced all day !.