I wrote the book on this one! Just about ANYTHING is possible!
Rover V8 is probably the most oiften done one, followed by Ford V6.
Both of those can be done with standard parts from Rover Catalogue, and or commercial conversion kits.
Plenty of kits to fit diesels from Peugots, Fords, Rovers, etc, and where 'interchangeable' implication is this could allow fitment of petrol equivilient.
For example, conversion kit used for Montego engine 'Perkins Prima' diesel, makekes S3-box look like a VW one, to the engine, so whatever enines are fitted to that, SHOULD go on prima adapter; so the Golf 1600GTi motor, or five cylinder Audi Engine! Rover 'O' Series, the 2.0l Montego engine, which in EFi guize was pretty potent, in Turbo form even more so, challenging the Cossies for acceleration!
Then you have the 'Ford' adaptors; makes the SIII box look like a Ford Sierra 5-speed to the engine, so you could fit, 1600 cross-flow; 2.0l pinto, Sierra Cosworth Engine, or one of the V6's more usually attached!
THEN! you have the possibility of using 'custom' engine adapter...... in which case there is almost NO limit to what might be possible!
Fitting Triumph 2.5 saloons used to be a popular one for hill-rally; and I know of one person using a Honda/rover 2.5V6, a few BMW straight sixes, a few Jag sixes, even a V12, and more than the odd Yank big-bore V8!
Oh, then there's the GMC and Holdon Conversions, and gawd knows what can be done with Nipponese motors; heard of some-one wanting to put a Lexus engine in a Land-rover!
And depending on what takes your fancy, or what you can lay your hands on you DONT have to stay with the Series gear-box, you can use almost any you like, with or without a transfer box, and again, with adapter plates, use any permutation of engine, box and X-fer......... which pushes things down towards the axles....... and suspension...... and brakes!
What is your 'reason' for wanting to put a different engine in there?
What are your circumstances?
If you are seriouse, most conversions or at least 'kinds' of conversion have been done; but some are a LOT easier than others, and some are more likely to work, others more likely to break!
But unless you are a mechanical masocist (probably - you bought a Series Landy!), and / or have some very good reasons for soing a conversion, AND some pretty good mechanical dexterity, best thing to do is stick with the trusty old four-pot!
Its NOT such a bad old engine, and fettled, they can reveal a level of performance that, OK wont set the earth on firfe, but remarkeably more spritely than you'd expect!
A few considered 'tweeks' on top of that, and you can even get the kind of power out of them that challenges that from a Rangie V8!
