Yeah that's the theory and I grant you I must be the unluckiest V8 buyer but
V8 £250 (not that I found one for £250)
You need something to pick it up (van hire £40)
In my case on strip down corroded bore
Engine in bin start again
V8 £250 (not that I found one for £250)
Corroded injector pins new set of injectors £400
Head gasket failed £100 if you do it yourself
V8 runs hot so new rad £80
New fuel filter need high pressure pump from somewhere £20
Probably want new engine mounts, the temp gauge won't be right, there will be some fabrication here and there it'll run hot the engine's lighter so the springs will be higher, and the exhaust will need some work.
I probably clocked up £2000 changing from 3.5 carb to 4.2 MS, partly cos I'm unlucky and partly cos some jobs I don't trust myself to do properly
This is probably worst case but cylinder head, camshaft, and carb was easy. The thing is still bulletproof, still has the right engine.
2.25 uprated is more reliable than a V8 I would say.
If you want reliability carbs are more reliable than EFI. I accidentally ran my 2.25 with no coolant and only noticed when the oil started to smoke and it was still working fine after wards.