[updated:LAST EDITED ON Nov-25-02 AT 12:44 PM (CST)]I have a '55 first series GMC 250 panel. The parts that I can use from 1/2- or 3/4-ton trucks are from the doors forward, but all the suspension and driveline parts are unique to the 1-ton. Sheetmetal, glass, interior are all identical, I ordered most of my truck out of the CD catalog.
The items I found difficult were:
1) The rear gears are 5.14:1, which with stock tire diameter gives you a top speed of 40mph. Finding a set of 4.10:1 was troublesome; there's a carrier tension bolt on the 1-ton diff, which means you need a specific (read: expensive) set of gears. Because the vehicle weighs 3.5 tons empty, I didn't want to go with too low a number.
2) The leaf springs are 1/4" wider than the 1/2- or 3/4-ton springs, so if you need to replace any parts, you're going to the wrecking yard. I had a broken main leaf on the rear, and ended up buying a pair of complete spring packs, restoring them off the vehicle, and installing both replacements at the same time.
3) Spindles and wheel bearings are beefy, and therefore rare. You'll find that cost and availability will point you toward Timken-style bearings (which last longer as well). If you find a damaged spindle (as I did), all I can say is good luck.
4) Wheels and tires are always an issue. With 1-ton rigs you have 8-on 6.5" bolt pattern, but you still have the narrow backspacing problem. I found a set of 16.5" rims with 3.75" backspacing, but they're 1.5" wider than the stock rims. The tires rubbed on the fenders. My rig is a work truck, so I rolled the fenders with a wood rod from the coat closet. If you plan to go to a car show, DO NOT do this. I do not recommend keeping split rims unless this is 100% resto/show only.
The question of "all original" is something each of us has to address in his own way. I chose to keep the rig as close to stock as possible, with upgrades in invisible places (12v internally regulated alternator, electric wipers, dual-stage power brakes). Whatever you decide, assume that you will have to disassemble everything, ESPECIALLY if you're getting some else's half-done project.
Best of luck,
Hedgehog
"Pass the cutting torch, I'm done f***ing around." -hedgehog
