What Are These Crossmember Brackets?

[Jahloha]

So I was planning ahead and thinking about my exhaust when I started reading threads on members cutting 4" circles through their crossmember, which I really like!

But, in all of their pics I notice that they do not have some brackets that my frame has. What are these for? Do I need them? Should I still consider running my exhaust through?

Thanks everyone!

Here is the routing I would like to run


Here is my truck frame with these additional bracket/supports:

[Sammy]

No doubt. Someone added those it appears. They will need to go to run pipes through your cross member.

[Cash3481]

I've had a few trucks with those braces... I think they are on 3/4 trucks, don't quote me. It's been a while since I had a truck with them but those are factory.
They will have to go for your exhaust to run through there. Someone will post the option/reason some trucks had them.

[Sammy]

Could be Mike not familiar with 3/4 ton. His pics looks like a welded after thought. Must be to prevent frame twisting on heavy loads.

[Jahloha]

Originally Posted by Sammy

No doubt. Someone added those it appears. They will need to go to run pipes through your cross member.

Thanks, I assumed so.

Originally Posted by Cash3481

I've had a few trucks with those braces... I think they are on 3/4 trucks, don't quote me. It's been a while since I had a truck with them but those are factory.
They will have to go for your exhaust to run through there. Someone will post the option/reason some trucks had them.

Originally Posted by Sammy

Could be Mike not familiar with 3/4 ton. His pics looks like a welded after thought. Must be to prevent frame twisting on heavy loads.

Cash & Sammy:

I was thinking maybe thats why, its a 1970 C20 and what I believe to be a camper special. Would that be the reasoning?

Last thing I want to do is remove these, run the exhaust, then have the frame or something tweaked after everything is back together.

Also, Cash, did you ever remove these braces on those trucks of yours?

[uncle]

Only ones I've seen those on are big block 3/4 trucks.

[Jahloha]

Originally Posted by uncle

Only ones I've seen those on are big block 3/4 trucks.

Thats weird bc I am almost positive this truck had a 350 sb in it. Now I have more questions!

[Cash3481]

Check you SPID and the exhaust mounts above the rear end. It might have been a BB truck originally. I'm not sure its a BB only item but Uncle may be onto something!

[Jahloha]

I know when I was tearing it down, there was only one exhaust pipe and muffler. So where would these mounts be on my frame?

I am getting super intrigued here!

[Jahloha]

Here is my SPID, it says 350 sb. So still trying to figure out why I have those braces.

[70CHEVYBB]

I have them on my 70 3/4 ton. I converted it to 1/2 ton and adding a high hp big block. I am leaving them for added frame support

[uncle]

Not saying that's a given but that's only ones I've ever seen them on. And coil spring only for me. Are yours bolted or riveted on? Looking at your build sheet, maybe it's 3/4 heavy spring thing?

[DaHos]

FWIW, They have been on all 3/4 T trucks I have had.........small or big block.

[Jahloha]

They are riveted in.

It's starting to look like I should leave these in, which is fine.

But it's curious I don't see these on other frames often. (Saying this as a newbie)

[FirstOwner69]

My 69 3/4 ton with 350, TH400 and coil springs has them.

[Jahloha]

Originally Posted by FirstOwner69

My 69 3/4 ton with 350, TH400 and coil springs has them.

Way better picture, thanks FirstOwner.

[Sammy]

Some states will allow a turn down after the cab, some just require exit behind the cab to the side. Those are some of the possible options if ur state allows it.
Just when you think you have these year trucks figured out you get educated again.

['68 Newtricks]

I think it's a 3/4 ton thing. My '68 C20 350/350 camper special had them.

If you aren't using the C20 as a 3/4 ton truck, I vote pull them off. What's the difference between a long bed C10 and long bed C20 when it comes to those brackets. I mean, at least you still have a thicker frame.

[Jahloha]

Originally Posted by '68 Newtricks

I think it's a 3/4 ton thing. My '68 C20 350/350 camper special had them.

If you aren't using the C20 as a 3/4 ton truck, I vote pull them off. What's the difference between a long bed C10 and long bed C20 when it comes to those brackets. I mean, at least you still have a thicker frame.

Good point. I dont haul much at all, but when I do load up, I want this truck to be able to pull without concern. But your point is making me think!

I am taking the frame in for blasting tomorrow, should give me some more time to consider what to do before I paint...this weekend hopefully.