So, I've been considering redoing the pulley system on my FB. I had the stock, then no emissions and the "yoohoo" belt setup, and now am running the gilmer. I think a "tooth" style belt is the most effective, but also the most expensive. I'm thinking on doing a "Gilmer" style, but doing it in a different formation and with different sized puleys. I'd like to allow for the opportunity to use the relocated alternator setup. The "main" pulley would remain the stock size for ease of timing etc., but I'm thinking of increasing the size of the alt and water pump pulleys. This would help with 2 things, it would help to eliminate cavitation in the water pump at higher revs, and it should give longer life to the bearings as well as they would be turning less and at a lower rpm rate. increasing the size of the alt pulley shouldn't matter as the alt charges at idle just as at 5,000 rpm. but I'm not sure just what rpm is needed for adequate flow from the water pump for cooling. Any input on this would be appreciated.

 

So, nobody knows this stuff, or nobody's gonna share?

 

Unless this is a track car, under driving your alternator and water pump is a bad idea. You'd be surprised how dramatically a small increase in alternator pulley diameter can affect voltage/current output. There is such a thing as spinning it too slowly to produce the current you need. An underdrive pulley on my 100A FD alternator will barely charge my battery at idle. Same goes for the water pump. There's no reason to sacrifice cooling ability because you're worried about high RPM cavitation that is very unlikely or water pump bearing life.