I missed this thread when it first started but I can add a little to the Elan forced induction topic.
In 1964 I helped a friend install a Shorrock supercharger in his Elan. I do recall it went like stink but it did have some minor problems. It had its heyday, just one! when it won its class (although its debatable whether it was classified correctly) in a local sprint. It got its winning run win in spite of crossing line travelling backwards!
The owner was a supercharging enthusiast and ran as a road car, a frogeye with a full race Formula Junior engine to which he had fitted a blower. He did the same to the Elan with the larger Shorrock unit (C142?) that was mounted in the nose of the car using a drive shaft passing through a hole put into the radiator. An Austin Seven fabric/rubber driveshaft coupling was mounted on three stud in the bottom pulley. The 2" SU carburettor went directly on the blower inlet and aluminium tube and hoses took the compressed mixture to the one-into-four manifold (my handiwork).
As a road car it was great, I doubt it would have had long term reliability and it suffered from the carburettor icing but it was fun. No work whatsoever was done on the engine to prepare it for supercharging and being much younger then neither of us knew much about it, it was all trial and error really.
The reason the car crossed the line travelling backwards was the the rear wheels locked up when the supercharger seized solid. We found at afterwards that the larger Shorrocks blower had an absolute upper rev limit that was a bit lower than the twincam went to!
I still have the SU and the manifold, in fact I fitted them to my S4 when I took the Webers off to overhaul them.
Ian