As for size of pulleys, you need to consider the operating rpm of the engine. I bought the March Performance Serpentine Belt Kit (Alt, WP, PS Kit) which worked perfect when I had the TH400 installed. I would regularly have the engine turning more than 1800-2000 rpm which is enough to turn the alternator fast enough to start charging. Now that I put the 700R4 in I have to make sure I rev the engine to over 2000rpm to get the alternator to start charging. The engine rarely sees 2000 rpm now, unless I put my foot in it. Not complaining, now I have a reason to put my foot in it!
