My 66 Service Truck Build Thread

[66-PMD-GMC]

After checking auto-zone, checker O'Riely's and NAPA I found the same part number for 63 3/4 ton and 79 3/4 ton A-arm shafts. In fact they used the same A arms for over 20 years.
They bolt directly in. They are the same upper and lower. I have a 79 1/2 ton suspension that bolted directly to my 63 cross member with no problem whatsoever.
I have no idea as to the interchangeability between 1/2 and 3/4 ton.
The reason I had to use the cross member on the 66 is because I used the 79 motor mount plates and the contour and hole pattern is different on the different year cross members where the plates bolt on. The 79 plates made my Pontiac transformation a bolt in deal.
If I hadn't used a Pontiac motor in my build I may have opted to leave the cross member in and not change it at all.
Frankly, you could pull your spindles only and bolt them to the 63-66 A arms.
I could do that swap in 3 hours total.