Re: 3 on the tree
 

Mel or Steve -

Please take a look at this truck.
http://6066gmcclub.com/forum/showthread.php?t=47666

It has 8 hole wheels and definitely a Dana rear. You might want to look at your truck to see if you have one of those in there now. If you do, then all you might need would be a gear swap. If not, then this could be the rear you might want to look for, because it would be the right width.

Ray

Re: 3 on the tree
 

The floor on a 66 is different than the earlier trucks. its like the 67-72. the auto and 3 speed rigs have a solid floor. the 4x4 and 4 speed trucks have a bolted in high hump. You have to cut out the floor and some of the firewall and graft in the corresponding high hump parts. Also any 420 trans from 47-67 will work. however there are 4 yoke sizes used 1310-1330-1350-1430. There are 2 case styles that were made. The best ones are the 65-67 with the extra ribs cast in the case. Finally nearly all 47-67 gm trucks with a 4 speed have the 420 trans. There is the odd new process 435 in the 60's.

Re: 3 on the tree
 

Not necessarily. I have had 3 '66 GMCs and only the 1000 had the one piece floor. The 1500s have had a removable hump.

Re: 3 on the tree
 

You have to watch out on the 54 & earlier transmissions. Some of them were made for a torque tube. You can identify these by the ball seat machined into the bearing retainer.

Ray