it doesn't matter to much but years go(pre 1975)we would put it where the exh pulses even out. a good way to find that is to rev the engine and look for the blue spot to end on new pipes or wipe a some light oil on pipes when its cold and look for the hot smoky spot to end and put it there to split the differences. experimenting could find that sweet spot. but even easier, install where it intersects at a point below the transmission tail shaft housing
Last edited by silverodster; 01-13-2011 at 12:08 PM.