Just rough text so far, will fill out with pictures soon.
The problem is that the Toyota fork-lift alternator that we are using is only tested up to about 7000 RPM. It also comes with a single V-belt pulley. The Rocam has a large crank pulley, with 6PK grooves. If you’re revving the Rocam at 6500 RPM, and that’s fed to a much smaller alternator pulley, then the poor alternator will get fried real quick.
So the simple answer is to put a bigger, 6PK pulley on the alternator. The Rocam water pump pulley is ideal, but you do need to make some mods to have it fit. A trick suggested by Hermann is to use the original steel V-belt pulley and mount the water-pump pulley on to it.
First step is to find the pulley. This is a common Ford part, and your local dealer should have one. Ours cost R57 (incl VAT), which was amazing.
Deon then went on to mount the water pump pulley to the alternator. Step 1 was to make the pulley center hole bigger, to center it on the v-belt pulley. Then he scored a groove on the pulley, and accurately drilled 3 evenly-spaced holes. Using the bigger pulley as a template, he drilled the same holes through the v-belt pulled. These holes were tapped, and A could then be mounted to B.
Brilliant!