C notch or not

[vht]

My 51 has the TCI mus 2 front susp, and rear 4 link with coil overs. 2 in drop front spindles also. None of this is installed yet since I'm working on the truck. I'm going to box the frame and I was wondering how much of a notch I'll need over the rear end. I've got some 2x2, 1/4 in wall that I was thinking about making it out of instead of doing the regular cut in the frame. I would think this would be stronger. I was going to weld it up, notch where it goes in the frame, weld it in and then cut out the portion of the frame. I don't know how much clearance I really need. The 4 link brackets are installed on the frame already so I thought I could install the bars and rear brackets and find out where I need to be.

[Speedbumpauto]

Not with any certainty. You need to have the front at least tacked in and assembled to obtain a ride ht. Then set the rear end in place and mock up rear ride ht with whatever rake/stance you want with the shock compressed about 1/4 to 1/3 of the travel. On mine it was about 1 1/2" compressed and it left me about 3 1/2" travel left. Cycle the rear end to full compression on the shock and that will tell you how big the notch has to be, adding a little for clearance. Make sure you are using or making patterns of the tire sizes you intend to use. All of these things can be tuned slightly after construction to make it sit exactly to your satisfaction.

[mr48chev]

You need enough room over the axle to give you clearance for what the axle will move or the truck will drop if you carry a load. That load might be two duffle bags, a cooler and two lawn chairs or it may be eight bags of sackrete for a home project. On a leaf, coil or coil over suspension I'd say you need a minimum of 4 inches above the axle and five or six might be better. On a bagged truck you need what ever keeps the frame clear of the axle when you air it out.

One of the mistakes I have to correct on my truck is the lack of notches over the rear axle. I broke my frame right above the axle on the drivers side from the axle hitting the frame too much. Sitting static I had maybe two an a half inches of clearance and that isn't near enough. The truck was thrown back together from a bare frame and the cab sitting on a pallet to a running truck in three weeks in 1989 with the intent of tearing it back down after driving to two events and life got in the way of ever tearing it back down until now.

[vht]

Thanks guys.

[c6_rob]

I say notch it. The bigger the better.

How low do you really want to go?

This is what it takes to lay running boards. Its a notch plate kit from Gambino.