I am still having trouble with the tranny popping out of second gear while decelerating and not wanting to downshift from third to second. All rods are adjusted properly and nuts are tight
Any thoughts??
I assume your talking 4 speed. Using the naming convention from a 1970 factory service manual:
Popping out of gear is usually caused by worn out "shift struts". There are 3 of them that fit into slots in the syncro clutch gear (splined to mainshaft), and the sliding syncro clutch sleeve is held in place by the 3 shift struts. If the struts are worn and/or the strut springs are tired, the sliding sleeve won't stay in place and the trany pops out of gear.
Not wanting to downshift is usually worn out syncro "stop rings" and/or worn out cone on the gear itself (second gear in this case).
Sounds like the trany is tired, and in need of rebuild. Passon Performance has a rebuilt 4 speed on ebay right now for about $600, which could be alot cheaper than buying all the parts, especially if anything major is out of wack with your current trany, such as if you have to start replacing gears.