Trailing Arm Lengths and my P10 project

[EVRLET]

I've been doing some research on the importance of trailing arm lengths, if there is even any importance to them. Why? I have a 1973 P10 step van and was looking at replacing the rear leaf set up. The wheelbase on a P10 is 102" and the C10 is 117.5". I can't just bolt up the C10 trailing arm set up to my P10 because it would place the trailing arm cross-member right up to the back of the transmission.

I have a bagged 67 C10 with full porterbuilt and looking at those trailing arms, I don't see why I couldn't get tubular trailing arms at a shorter length and have the cross-member right where it needs to be on my van's frame.

Does anybody know why trailing arms have to be a certain length and what potential problems may occur if I made them shorter?

[Aberdare]

Originally Posted by EVRLET

I've been doing some research on the importance of trailing arm lengths, if there is even any importance to them. Why? ....
Does anybody know why trailing arms have to be a certain length and what potential problems may occur if I made them shorter?

I have what I THINK is a 1963 GMC Value Van (Documenting is in progress), and yes, the trailing arms DO need to be a specific length to fit the chassis... but don't be too alarmed as the same arms were used on a variety of Light duty chassis from 1961-1969... so if you do some bone-yard hunting, you can still find some decent arms from another wreck if you need to replace them.

Abe

[kenny_strong]

Just sell it to me and I will take care of it

[67LS3GMC]

You can shorten the arms , BUT you will need to adjust the height where they attach to the cross member to correct / maintain proper the pinion angle . ( or use shims). I know instant center will change, but I don’t believe you’re building a drag truck .
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[OARNGESI]

With all the work just do a 4 link instead

[EVRLET]

Since I had the extra trailing arm set up lying around, I figured the only “work” to be done was shortening the arms. I did consider a four link and that’s still an option.

Here’s a pic of my beloved, uncut body P10 riding on some 17” Billet Specialties. This is stock height and when I decide which suspension direction I go, I’ll post a pic of a much lower ride height. Damn van was so hard to find and I got lucky finding this beauty with a gen 1 350 with power steering and brakes. Minus the wheels, this is exactly how it looked when I bought it 2 years ago.