Nick, I ran my RP for 1000 miles with a 3-bearing engine recently while I was putting together a suitable 2-bearing unit.
The 3-brg engine sits about 5/16" higher at the rear, the main issue I recall was it was rather tight getting it in and out of the car - I had to undo the throttle pedal cross shaft to squeeze it under. And yes, you might need to juggle things like the flywheel cover - but I had no need of a hacksaw, it went together, and the bodywork was untouched.
I had no real issues at the front end and it worked with the rad shell acceptably well. It has been pointed out elsewhere that the angle of the crankcase feet differed, not just their vertical position, so the front is more or less in the same place.
In short it can be done with minor inconvenience but no surgery (- on my car at least).
The Hardy Spicer propshaft is another matter, and is bound to foul the handbrake mechanism. I removed the little "bobbins" which hold it off the chassis member and substituted an assortment of washers which was tweaked until it cleared acceptably. Some trial and error will be needed there. You can also grind a bit off the rivet head which it tends to foul on.
The 3-brg engine sits about 5/16" higher at the rear, the main issue I recall was it was rather tight getting it in and out of the car - I had to undo the throttle pedal cross shaft to squeeze it under. And yes, you might need to juggle things like the flywheel cover - but I had no need of a hacksaw, it went together, and the bodywork was untouched.
I had no real issues at the front end and it worked with the rad shell acceptably well. It has been pointed out elsewhere that the angle of the crankcase feet differed, not just their vertical position, so the front is more or less in the same place.
In short it can be done with minor inconvenience but no surgery (- on my car at least).
The Hardy Spicer propshaft is another matter, and is bound to foul the handbrake mechanism. I removed the little "bobbins" which hold it off the chassis member and substituted an assortment of washers which was tweaked until it cleared acceptably. Some trial and error will be needed there. You can also grind a bit off the rivet head which it tends to foul on.