I'd go with the alternator conversion too. I used a kit from Rimmer Bros which contains all the various brackets and pullies.
However,depending on the type of exhaust manifold you gave fitted, you do need to be aware of clearance between the manifold and the alternator.
I did initally fit a Lucas ACR series alternator to my Plus 4 (with a non original tubular manifold) but there was very little clearance between on of the headers and the plastic cover at the back of the alternator. I've since been given a GM alternator (which I presume is the same as the one Button mentioned above. Its more compact and clearance is not now an issue.
Arwyn
