MH...
Thanks for your info. I had my jackshaft at a shop who disassembled it and he said there were no spacers in the front, that the pulley was up to the bearing. He still has all the parts as I sending it out for clean up (media blasting). Markings on the shaft seem to indicate no sign of a spacer. That bearing sits next to a shoulder on the jackshaft itself. It was only 14mm. I need to talk to him again to make sure there was no spacer but he said there was not when I did talk to him before. The middle and rear bearings were 12mm with thin spacers inside the clips that are on the outside of those bearing races. I have been told to not put in the middle bearing and have decided to follow that. Johnny Woods does replace them but note that said that they are "normally spun" and he has to repair the jackshaft. Indicates a problem. Steve Liebenow says definitely to not replace the center one siting problems. I did place my shaft carrier on a flat counter and found that the center to bosses that are to meet the intake manifold are about a mm+ short of the length of the outer two. Either the stock intake manifold has that slight step up or thin spacers are needed there. Have you checked this? Also, my shaft is bare metal, not painted black like I think earlier ones. My car is #700. I have considered thinning the rear spacers to accept a slightly wider bearing like 14 same as the front. If I don't have a spacer on the front as I was told, I am reluctant to trim the shoulder on the shaft to accept a wider bearing.
Bosswrench...Re "whipping problems or just for appearance, I considered taking a bearing and making the inside diameter slightly larger such that it does not contact the center shaft bearing race but could put a damper on potential whipping if the tolerance was not too big. Seems it would have to be out of balance to do any whipping.
Is there any choice between double or single row bearings in this application? Is double better?
Terry