[Roadtrip]

You're looking for the wrong stuff. What you need is an "Engine Analyzer." These were common before the advent of electronic ignitions. The one I have is about 20 years old and still works perfectly. It's a Sears Penske Model # 244.21033, about the size of a cinder block. I don't even know if they sell them new anymore given that the new cars are all have EFI and electronic ignitions.

Mine measures:

1. Point resistance
2. RPM
3. Volts 0-16 & 3-32
4. Amps -5 to 90
5. Ohms 0-40k
6. Spark output

The generally come with all the cables and shunts necessary to test a generator or alternator for max output.

I looked over on Ebay (under "engine analyzer") and there are loads of them available in good condition for $5 -$20. If you get one off ebay, be sure the instruction booklet, cables, and shunt come with it. The instruction book is really important because it will show you exactly how to make the connections to test what you want to and not damage something, yourself included. Even an anemic Bosch 30A alternator can really stand your hair on end.