55-amp is the early one and it most likely needs an external regulator. If you find a later alternator in the future, you can machine the ring-shroud to accomodate it. Find out what alternator make does he have and what pulley size. If it requires a rebuild, the manufacture makes a big difference. The larger pulley is the one you want (I believe it is about 3.75" vs. the smaller 3.25" one). Use a 5" crank pulley so you do not spin the alternator/fan too fast. I would bump up the compression a bit and play around with the timing. Eventually when you build the 2270-cc, you can build it to create the heat to warrant the extra cfm that the 911 fan system produces. Looks like you are doing the same as I am in regards to engine plans. I plan to go with a RAT 2270-cc eventually.
If you need a ring-shroud, I have several available.
Keep in touch if you need help.
