[Jeff H]

I just noticed that all the lights are very dim at idle but when I rev it another 2-300 rpm's they brighten up(this is on my 70 L78 Camaro). I checked the alternator and it's an 834 unit with the stamped 2.75" pulley. It seems to be spinning too slow at idle. Does the correct 837 alternator with the machined deep groove pulley spin at a higher speed at idle or could I have other issues? The car has an HEI distributor and I'm not sure what else isn't stock at this point. Can anyone tell me what size od the stock crank pulley and alternator pulley should be for the L78 setup? I want to keep it as close to stock as possible so that may factor into the solution. Any thoughts?