Factory installed rear sport bumper??

[71CHEVYSHORTBED402]

I had to modify brackets to get this far, and want to check some things. At this point I'm doing this without a bed. Happy to say the modification appears to work, I'm mostly concerned about the pitch of the bumper.

Irony is I saw an example truck on the way to deliver the outer brackets for cuts this morning. Very cool C20 and nice OEM brackets. Though its bumper seemed to sit a pinch too low I think my pitch is good or close.

Hoping someone can measure where it's possible per the pictures below. In addition to that, if you can offer how far the top of the bumper sits above the frame rail that would be helpful as well. Mine is currently approx. 1/2" above the frame rails.

The fourth pic is for entertainment I've seen double tags, right packages with wrong parts etc. but never this.

Thank you


Edit: For whatever it's worth the pictures are for my bumper in it's most forward and highest position, pending any more mods. Yeah I have to do this again with the bed on, but it would nice to know I'm on the right track. That is unless you have OEM brackets available for a 2wd, SWB with leaf springs

[Richard]

Did you ever look at the dimensions I posted in your thread here? https://67-72chevytrucks.com/vboard/...umper+brackets Curious why you post dimensions to the end of the frame and the rear bolt when they are what appear to be different? If the dimension from the bolt hole inbetween the shackle hanger to the back back bed mount bolt is the same. You should be able to mount SWB 4x4 brackets with the shackle hole and drill the inner bracket with the hole located in your frame. Just trying to help. Believe there may even be another hole in the reinforcement piece that may be close.

[71CHEVYSHORTBED402]

Originally Posted by Richard

Did you ever look at the dimensions I posted in your thread here? https://67-72chevytrucks.com/vboard/...umper+brackets Curious why you post dimensions to the end of the frame and the rear bolt when they are what appear to be different? If the dimension from the bolt hole inbetween the shackle hanger to the back back bed mount bolt is the same. You should be able to mount SWB 4x4 brackets with the shackle hole and drill the inner bracket with the hole located in your frame. Just trying to help. Believe there may even be another hole in the reinforcement piece that may be close.

Only because the frame rails are fixed & a bed is not, there's 3/16"ish play due the frame is slotted for the bed bolts. But yeah, I have to fit the bumper to the bed as well.

If I get your meaning about the rear bolt hole to end of the frame rail, that picture (not shown) was originally used to figure some things out. Yes the rear hole in the frame rails vary. I can't speak for all frame rails, but seems to me the space between the frame rails and bumper would be the same regardless of frame rail type from factory.

The 4x4 brackets don't work. Ironically if you drill through the reinforcement plate where the hole is in the bracket, that's the correct 5.3" bolt pattern for this application, but that puts the bumper well too far back. That and they don't clear the hanger rivet etc. They do not reproduce brackets for this application, the vendor's sale & descriptions in that respect are wrong.

I see you posted a picture in that other thread, thank you. You have the 7.1" bolt pattern using "4x4 brackets". I think your front hole is approx. 7.5" from the end of the frame rail. Mine is 6.1".

I got "coil spring" brackets to work after a mod, just wanted to see if they're on the right track before installing the bed. Here's a picture of a "4x4" bracket.

[71CHEVYSHORTBED402]

Just for demonstration. Figure the inner brackets would have the same issue since they're intended to line up.

For what it's worth, "4x4 brackets" were installed by someone else on this truck long ago, which was a disaster all the way around. Structure was bad, appearance was worse.

[Richard]

What is your rear spring length eye to eye? The stock ones on my SWB 4x4 are 52". I see you like to go down to tenths of an inch. Because I modified and extended my frame and cannot see where original ended I cannot help with the measurements you want.

[71CHEVYSHORTBED402]

Originally Posted by Richard

What is your rear spring length eye to eye? The stock ones on my SWB 4x4 are 52". I see you like to go down to tenths of an inch. Because I modified and extended my frame and cannot see where original ended I cannot help with the measurements you want.

It's only because the 10s stick is handy, though GM did engineer for bumpers in 10s.

My drop leaf spring eyes are 51.5/8" to the top of the shackle bolt & the hangers are 52". I checked my old leaf springs, the eyes are about 48 3/8". I don't know how much a load makes a difference, but the top of the shackle on the replacements is further back than OEM. Makes sense since they're drop springs.