70 C10 SWB Frame Measurement Needed

[xr4tic]

Hey all, hoping someone can help here.

I'm in process of installing a Summit frame brace kit and things aren't lining up. I'm trying to figure out if it's the kit or my shortened frame (done by previous owner)

I'm looking for a measurement from the rearmost upper rivet of the front body cab mount and the frontmost upper rivet of the trailing arm crossmember (see pic)

I'm off by 3/16" on one side and 1/4" on the other.

Top pic is from the instructions, bottom pic is what I have. I measure 29 5/16" on one side and 29 3/8" on the other, but my frame holes are 29 1/2" and 29 5/8"

I fear it's the frame because the holes aren't even the same side to side.

[bikeguy0@yahoo.com]

Frame specs are below for the SB. It doesn't have the measurement you're after but it does have two different ones you an use. The 43.03" and the 72.49" measurements from the reference hole just past the trans cross member location shown in the first photo. 2nd and 3rd photo go together and you could use the N or O measurement.

I just installed that chassis brace this weekend and had to open up the holes on one side of the chassis brace to allow the bolts to be 1/8" rearward due to the same issue. I shortened my frame and one side was just slightly 1/16 - 1/8" longer than the other when welded back together. I finally got it in there .

[xr4tic]

Thanks for the drawings Problem is, I still have the cab on the frame, I only removed the bed, so I don't have easy access to any of the gauge holes. On top of that, it's sitting in a driveway that isn't level.

I also don't have a reference hole by the bellhousing crossmember. If I'm reading the 1st drawing correctly, it should be 2.78" from the center of the crossmember, and there's nothing there.

Looking at another thread, seems someone else had to slot the holes as well, so I think I'll bolt the front in and just slot the rear piece as needed.
https://67-72chevytrucks.com/vboard/...d.php?t=837552

[A1971Blazer]

Originally Posted by xr4tic

Thanks for the drawings Problem is, I still have the cab on the frame, I only removed the bed, so I don't have easy access to any of the gauge holes. On top of that, it's sitting in a driveway that isn't level.

I also don't have a reference hole by the bellhousing crossmember. If I'm reading the 1st drawing correctly, it should be 2.78" from the center of the crossmember, and there's nothing there.

Looking at another thread, seems someone else had to slot the holes as well, so I think I'll bolt the front in and just slot the rear piece as needed.
https://67-72chevytrucks.com/vboard/...d.php?t=837552

I posted in that thread for having to slot some holes.
My frame was SWB to start with and the rear cross member rivet holes are where I started.
I figured they were oriented correctly and square to the frame rails, as they seemed to be, because they lined up perfectly.
All the slots I put in were in the front frame brackets.

[70STOVEBOLT]

If you still need the measurement, let me know and I will measure it after work.

[xr4tic]

Originally Posted by 70STOVEBOLT

If you still need the measurement, let me know and I will measure it after work.

If you can measure it easily, then I'd like to know, thanks!

[70STOVEBOLT]

Driver’s side measures 36 and 3/16, almost 1/4, and the passenger’s side is 36 and 3/8. I wonder why they are not symmetrical…. Mine is a ‘70 original SWB frame.

[xr4tic]

Originally Posted by 70STOVEBOLT

Driver’s side measures 36 and 3/16, almost 1/4, and the passenger’s side is 36 and 3/8. I wonder why they are not symmetrical…. Mine is a ‘70 original SWB frame.

Thanks! My driver's side was also ~1/8" shorter than the passenger side. Very strange.

Now I'm less concerned about the frame being out of whack, guess I'll just do my best to square up the trailing arm crossmember to the frame rails and call it good.

[bikeguy0@yahoo.com]

Originally Posted by A1971Blazer

I posted in that thread for having to slot some holes.
My frame was SWB to start with and the rear cross member rivet holes are where I started.
I figured they were oriented correctly and square to the frame rails, as they seemed to be, because they lined up perfectly.
All the slots I put in were in the front frame brackets.

Glad you mentioned that. I slotted all the holes on one side so the frame brace would line up correctly on that side without having to tweak it to fit. I only had issues on one side or the other based on which side I bolted in first. Mine is centered side to side at the trailing arm brackets and the frame is square to within 1/8 of an inch as I couldn't get it exactly perfect. I almost wish I would have just bought new frame rails from classic industries as I had to straighten a number of areas where they must have high centered the truck on a rock at some point over the last 40 years. That way I wouldn't have had to cut the frame, weld it, and deal with questioning if something wasn't square. They are just under $2K for new frame rails.

[A1971Blazer]

Originally Posted by bikeguy0@yahoo.com

Glad you mentioned that. I slotted all the holes on one side so the frame brace would line up correctly on that side without having to tweak it to fit. I only had issues on one side or the other based on which side I bolted in first. Mine is centered side to side at the trailing arm brackets and the frame is square to within 1/8 of an inch as I couldn't get it exactly perfect. I almost wish I would have just bought new frame rails from classic industries as I had to straighten a number of areas where they must have high centered the truck on a rock at some point over the last 40 years. That way I wouldn't have had to cut the frame, weld it, and deal with questioning if something wasn't square. They are just under $2K for new frame rails.

It should be OK if it will line up correctly and you can get the front end aligned to spec. I was lucky that my frame was in good shape to begin with.
Good luck with it, the brace seems to really stiffen the frame.

[HO455]

Originally Posted by xr4tic

Thanks for the drawings Problem is, I still have the cab on the frame, I only removed the bed, so I don't have easy access to any of the gauge holes. On top of that, it's sitting in a driveway that isn't level.]

Excuse me if I'm out of line here but, having the frame supported in a manner that ensures the frame is perfectly level is very important when installing or repairing frame components. If new components are installed and the frame is not level the frame will then be permanently locked in that twisted position.

If your surface isn't flat and level you need to shim your frame supports (jack stands) to get the frame level. Using a cheap 360 degree Lazer level and a tape measure can get you with in the 1/8 of level needed for most vehicles.

Once again if you've already done this please accept my apology. I've seen to many cars marginalized by poorly installed subframe connectors and/or roll bars.

[A1971Blazer]

Originally Posted by HO455

Excuse me if I'm out of line here but, having the frame supported in a manner that ensures the frame is perfectly level is very important when installing or repairing frame components. If new components are installed and the frame is not level the frame will then be permanently locked in that twisted position.

If your surface isn't flat and level you need to shim your frame supports (jack stands) to get the frame level. Using a cheap 360 degree Lazer level and a tape measure can get you with in the 1/8 of level needed for most vehicles.

Once again if you've already done this please accept my apology. I've seen to many cars marginalized by poorly installed subframe connectors and/or roll bars.

Good thinking....I was just assuming that part was a given...
I'm lucky enough to have a nice level surface to work off of...

[HO455]

You would think it would be, but 10 or 12 years ago we had a guy bring a nice mid 70's Camaro into the body shop to get his doors aligned. They were hard to open and you had to really slam them to get them to shut. We assumed they would need new bushings in the hinges but, after inspection we found the hinges were nice and tight. So we looked further thinking the car had been wrecked or something similar. The only thing I found was a set of frame connectors that looked newly installed.

After some discussion with the boss, he called the owner in and, after some more discussion, the owner admitted he had installed the connectors a couple months earlier. When asked how he installed the connectors he said he just jacked the car as high as possible on one side and welded that connector on before moving to the other side. He claimed not to own any jack stands just a floor jack.

Fortunately for him his welds were poor and not nearly enough so it only took me 3 hours to remove them and grind everything clean.

Then he paid us to install them a second time.

[xr4tic]

Originally Posted by HO455

Excuse me if I'm out of line here but, having the frame supported in a manner that ensures the frame is perfectly level is very important when installing or repairing frame components. If new components are installed and the frame is not level the frame will then be permanently locked in that twisted position.

If your surface isn't flat and level you need to shim your frame supports (jack stands) to get the frame level. Using a cheap 360 degree Lazer level and a tape measure can get you with in the 1/8 of level needed for most vehicles.

Once again if you've already done this please accept my apology. I've seen to many cars marginalized by poorly installed subframe connectors and/or roll bars.

That is a good point, and one I thought of before tightening everything down this morning.

I had the rear higher so I had room to work and get everything in, but I moved the jack stands to where the axle would be to try and simulate where the weight would be and levelled it out front to rear best I could before tightening all the bolts.