The Stovebolt Site Forums The Parking Lot Big Bolts front fender differences

I'm just wondering what the differences are in the front sheet metal of "big bolts" vs. the 3000 series trucks.

I know from outside to outside the big trucks are 74 7/8" vs. 72 5/8".

How much longer are they? How much taller are they? Whats the wheel well opening width?

Any help appreciated.

Knowing what year truck your working on would help others answer your question...

Mike B

54

The room for the engine is the same in small and large trucks, same distance from radiator to firewall. The fenders bolt to the cab just the same.

The big truck fenders are different enough for larger tires fit in them, a larger wheel opening.
Not sure what you're intentions are but pretty much the one advantage of the big truck fenders is to fit large wheels, 36-38" or so outside diameter works and looks good. They look funny with tires about 33" or less. Roughly speaking, your opinion/ideas of tire diameter and fender opening may differ.

I measured big and small truck fenders on the truck to the inside where the tires might rub them if an axle were too wide, or wheels stick out too far.

Small truck 68" width measured inside the front fender lip at bottom of opening, same both front and back edges.
1.5 or 2 ton AD front fenders (on the truck) 72" wide inside to inside of the lip at the bottom edge both front and rear of the wheel opening

So the big truck fenders stick out about 2" more each.

Grigg

On '41-'47, GM, full width fenders, while rare, do exist, the wheel openings are large, so they would look 'undernourished' with 33" or less tires as Grigg says for AD's above, but at least the tires do not stick out, whether legal or not in your part of the country.

Ed

I'm wanting a little extra width. I had read on another site that Big bolt fenders were 3" longer.

I actually found a 54/55 1st series front clip not far from here.

I'm only going to use a 29-maybe 31" tire, so these may not be worthwhile. May look funny.

I've seen guys widen fenders by splicing in a strip of sheet metal. I just cant bring myself to do it.

Here's hint of what I'm thinking, if you're at work, turn the volume down. http://s240.photobucket.com/user/ne...mp;_suid=1465847279924032982325348451835

If you get the 54/54 first, I need instrument panels(two piece) , so, please keep me in mind.

Thanks,


Ed

Not only are the fenders wider,They are Longer and Taller, as are the grill supports.
The hood is the same at the cowl end,but longer overall.
Once used a 2 ton rear hood brace(the piece the hinges bolt to),to replace a Rotted Out 3/4 ton brace.
A Friend Got Stiffed with a BIG Truck Hood,when He needed a 3000 series.
Unless You Use the ENTIRE Front Clip,It Wont Work!
regards,
steve sr.
p.s.And Oh Yes You can scavenge Good Grill Bars from the big trucks,they are only slightly wider,but the same length.(slight diff, profile)

Good point, it's all or nothing on the AD front flip, either use 1/2 through 1 ton or 1.5 and 2 ton. Can't mix and match between them.

Cab to axle centerline is what really concerns me. I don't want to have the wheels offset in the opening. The rest, I can deal with.[

Consider that the AD 3800 and 4100 use the same frame in every detail except how the bumper mounts.
The leaf springs in each truck also position the axle in the same place front to back.

No problem

I was looking at the 3800/4100 specs in the assembly manual this morning, that never crossed my mind.

Good information here. I never realized there was this much difference. I only suspected a larger radius on the wheel opening, never suspected all the other differences.

47-54 GMC 400, 450, and 470 series fenders are even wider than the 47-54 1 1/2, and 2 ton Chevy, and GMC fenders.