Boxing a frame

I mention earlier that it is 2x2 square tubing! Set on an angle.

Its a rail within a rail. Way stronger.

Some company has a boxing kit that mimicks the wider convertible frame rails. Has something like two dozen pieces to it - rediculous! And the cost was silly. I tell ya, my idea is pretty damn good and cheap!

 

Complete control arm support

 

That all looks good.

 

Good job. Should be strong as hell!! "Triangulation" is the key!

 

Thanks guys! Next I am welding up the factory seams before boxing the big crossmember.

 

Crossmember is now complete. Frame is upside down

 

Ready to narrow frame rails about an inch - enough to get rid of the slope to the outside.

Plasma cutter taken to 1/8” plate steel after making a pattern.

 

Frame is finito! All done!

Once I weld a few nuts into the body to engage the formerly “dummy” body bushings by the rear spring cups, the body will be back down on the frame. Yahoo!!!

 

The back looks great. Are you able to adjust your transmission crossmember font to back? Is it also positioned at the correct height location from stock. If it is higher or lower it can change shaft angle and possibly cause a vibration.

 

Hey Brian, its fixed in place fore and aft based off the position of the factory holes for the 455/ th400 combo. Before the boxed rails I marked out their position as well as the height of the crossmember’s trans mount “pocket” relative to the top of the factory rails. Straight edge across, ruler down to that surface gave me 4 and 1/8th in on my car.

I’d have made a tubular cross member if I had a tubing bender.

 

Anyways, the body is off those giant sawhorses and the whole thing is back on the ground. I currently have 275/60s on 8” rims. With the frame pinch I can now go an inch wider inboard (after some sheetmetal mods), and over an inch outboard. Looking at MTs 315/60 ET Street R.

 

315's are a Big tire,..the height will get you before the width,..325's will fit with stock frame and 3.5in exhaust

 

Hugger is correct. I run 325/50/15 without any modifications.

 

So I did the frame pinch for nothin’?!?!?

As it was, with the 275/60 I had a half inch clearance inboard and 1.5 outboard. That was with 8” rim and 5.25” backspace. Original 10 bolt 8.5 rear end

Are you using 10” wide rim? What backspacing? Did you have to trim or fold in the wheel lip?

 

10in rim with a 5.5in back space I did roll my lips but it was more for just extra peace of mind,..but clearance was minimal everywhere but would only rub on hard bumps and whatnot nothing that would have hurt a tire or anything

 

15x10 with a 5.5” backspace. This will clear without pinching the frame arches,but now you will have some room. A 5.75” backspace would be ideal,but if you are running the factory A-body rearend,a 15” rim will hit the shock mount. I did not modify my wheel well lips or inner fenderwells. A 315/60/15 tire will require some modification to fit up in the wheelhouses.

 

Thanks guys, much appreciated.

Brian, I noticed the shock position issue. Looks like I could relocate the hole a little higher and cut the mount. Maybe weld in a mount stud rather than keeping a hole so shock is as low as possible. Does that seem reasonable?

Hugger, that car sure sits nice! Is it lowered some? What springs are in the rear?

 

That was several years ago,..but that was stock gs rear springs with 3.5in back space wheels I narrowed it an 1.75 on each side the simply cut the shock mount leg off and moved it inboard and welded back to where I cut it but on the opposite side of where it was originally if that makes sense. I spent 2k building a rear end just so I could run a 3.5in backspace wheel...ha

In the pic above I eluded to them being 5.5 but that was simply for visual purposes.,the wheel is sitting just as it would with a 5.5in backspace wheel tho,..I ran 5.5in weld draglites with 325/50's for while also

 

I put theses on my 71.

https://www.ebay.com/itm/Rear-Shock...FaldG3Sa:sc:ShippingMethodExpress!06422!US!-1

 

Dragdoc,
Fab some new mounts that relocate the shock directly behind the lower control arm. This will take some angle off of the shock and help 60-ft times. Moser does this with their A-body housings,and Strange has recently done the same. It pretty much copies the G-body shock mounts.