Sounds right from from I've seen, Re the 400 series. Attached a few photos of what my fenders, and linkage looks like. (probably much better than my description) There is a small portion of the kingpin sticking out the top of my spindle, It measures 1.105" so a little bit smaller but I suspect it's the same 1.109" kingpin. For size ref in the pics those front tires are 7.50/20 (and not that it matters but my rears are 8.25/20) I edited the last post, had a brain fart when I noted the bolt pattern, so I gave you the wrong info there. Should have read (large pattern) 5 lug.

Matt
Attachments
gmcfender1.jpg (56.74 KB, 611 downloads)
gmcfender2.jpg (57.85 KB, 612 downloads)
gmcaftlookingfwd.jpg (59.9 KB, 609 downloads)
gmcfwdlookingaft.jpg (76.35 KB, 611 downloads)
gmcdriverssteeringbirdseye.jpg (48.49 KB, 612 downloads)

Last edited by 40_chevy; 02/03/2018 6:37 PM. Reason: additional info

1953 Chevrolet 1100
Grandpa's truck
Story in Big Bolts
1952 GMC 9700
Story in Big Bolts
1948 Chevy Pickup
"Two brothers; two trucks"
In the DITY Gallery