@patrickt - single wire alternators are usually built off of a GM core IIsi chassis , so that if you don't mind a GM alternator on your Ford engine I guess there is nothing wrong with them -
Technically though, on a serious note - most single wire alternator installations I have seen come into our hands, the core charge wire itself is undersized and can cause melting or fire if not upgraded to a larger gauge of wire. Many of these single wire jobs are pushing 95-100-150-200 amps and that can Kentucky-fry a 1960s vintage charge wire ( size or spec )
The original SPF harness is designed with a 65-75amp alternator in mind ( think 1965 mustang gt )
The installer should be upgrading this at time of install , if they are using a higher grade unit.
As for aiding you through this particular problem , I am sure Blas is capable at getting you where you need to be.