Theres a growing community of bike engined lotus (or locost
) 7s out there.
The 7 is quite a bit lighter than a 914, but I don't think that's a deal breaker.
The primary issues seem to be:
1. Bike engines scream, but there's no bottom end torque. This means that they don't make very good daily drivers, but are wicked on the track. The PCA will hate you.
2. Transmission/linkage issues. I believe the linkage in the 7 involves maybe a chain and a reverse box thingo (bike transmissions don't have reverse). These things break reasonably frequently and I think they also introduce some driveline shunt. You will probably get a sequential shifter out of it, and you should be able to use this in reverse (gah!).
3. Presumably you'd go watercooled, which comes with it's own issues (see V8, Subaru) - but nothing unsolvable.
All in all - I think this is all solvable, and you'd end up with a total screamer. Do it
.
BTW: There was a 4 wheel drive 7 built once with 2 busa engines - one powering the front wheels and one powering the rear. I'd like to see this done to a 914 before I die