sorry couldn't resist, never owned a stag but I think i'm right is saying they did have overheating issues?
When new, yes.
British Leyland didn't flush out the parting sand from the cast engine block, and all the sand tended to settle in the cross flow radiator restricting flow.
I completely bare shell restored mine in the early 90's and even though it had a factory exchange short engine, the block had a lot of sand still in it.
The other issue was the design of the oil filter element with glued cardboard end caps. These unstuck with the hot oil and tendered to move out of place, again restricting in this case, the oil flow. Unipart redesigned the filter in the late 80's, 10 years after the last cars were made.
So with both issues sorted, they are a reliable, high revving, OHC V8 engine.
We have a few owners that have achieved 250 BHP on fuel injection, not bad for a 2 valve normally aspirated 3lt engine.
I have my own EFI project that I need to finish using 8 individual throttle bodies!