yes ive done one, i had a big problem. i put it all together no probs but when driving the gears would lock in solid and occasionally it would make a loud grinding/screaming noise. i knew the gearbox was fine so that wasnt the prob. the engine was from an automatic car and the bush in the centre of the flywheel was made from a different material rather than phosphur bronze/oillight so this would cause the prob. £1.15 for the right bush but i had to take the engine off the box again.
this is only a prob on auto boxed engines, if in doubt change the bush. they are high compression engines and alot better.
more importantly, SD1's are lovely classic cars if you found one your lucky.