I looked up the ASP and BBK pulleys. The ASP crank pulley is listed as 34% underdrive, the alternator pulley is listed as 32% overdrive. BBK failed to list any information, even on their home page web site.
You could run a mix, but then you would have to spend a bit of time fitting the belt to find the correct length.

 

yea i even called bbk to find out the amount it is underdriven and were unable to give me a number...

 

Fitting a belt wouldn't be hard. Just run a piece of string around all the pulleys and then measure the length of it. 6 rib, 70 inches, 6040700 would be one of the common part numbers then. Or some are like 6K700. For my 93, it's 63.7" so you're basically looking for a belt in the area of 62-64" I'd think. Buy 4 or 5 and take back the ones that don't fit, just explain before hand what you're doing so they know

 

The ASP 945103 is a great set, buy them and be done.

 

im about to order up the ASP 520004 pulley. now for a belt size i should be looking for something between 62-64"?

 

in that asp kit they sell is the alternator pulley larger than the stock alternator pulley?

 

The alternator pulley should be smaller in diameter than stock, allowing it to turn more revolutions per foot of belt travel.