67-72 front crossmember VS squarebody

[Nitis]

First C10 brought up if it would be possible to put a squarebody front crossmemebr in a 67-72 frame since the squarebody can accomidate a LS engine while the 67-72 needs a custom crossmember

I cant imagine no one has thought of trying this up until now but I havent seen any chatter on it. COuld one fit or be made to fit with some slight modification?

Would seem to be much easier and less expensive than the custom ones being offered

[BLAZERMAN]

It's been done before, I know there are a few on here that used them in there big block conversions. It takes a little trimming and drilling, I posted an article from an old 4x4 Power magazine on how to do it but that's been years ago, I'll see if I can find it.

[First c10]

That would be great if you can find the article.

[BigRed76]

I haven't found any info to confirm it but I think its safe to say it'll work since you can swap a 73-87 2wd engine crossmember into a 67-72 2wd because the frame rails are the same width at the engine crossmember.

Do the 73-87 guys have to modify their engine crossmembers for LS swaps?

[Nitis]

No they don't. Sometimes a little tight for header which I could care less about but headers are tight in any scenario

[7dee2]

Here's one I'm aware of 72 2wd to 4x conversion using the later cross member http://67-72chevytrucks.com/vboard/s...9&postcount=53

[BigRed76]

Originally Posted by 7dee2

Here's one I'm aware of 72 2wd to 4x conversion using the later cross member http://67-72chevytrucks.com/vboard/s...9&postcount=53

I guess it's safe to say that not all 73-87 4wd trucks have the same engine crossmember because my 76 K10 I had a few years ago had an engine crossmember different from the one used in that thread.

[7dee2]

I would agree but have noticed that they are very similar. I've got one from a 73 K5 and an 84 K30 both look a lot like the 87 K30 used in the example I posted earlier. Differences I noticed had to do with strength extra bolts, tabs, etc but same basic shapes.

[Nitis]

Originally Posted by 7dee2

I would agree but have noticed that they are very similar. I've got one from a 73 K5 and an 84 K30 both look a lot like the 87 K30 used in the example I posted earlier. Differences I noticed had to do with strength extra bolts, tabs, etc but same basic shapes.

Big block vs small block?

[7dee2]

Small block, I believe the BB versions have an additional hole pattern in the stand to accept a 4th bolt for the BB motor mount. Just my observation hope it helps.

[BigRed76]

This is the best picture I could find of the crossmember on my 76. The actual crossmember part was virtually straight from one side to the other, it might have had just a slight bend. Then the motor mount pieces sat right behind the crossmember. And that was a factory small block truck.

But regardless of whether they are straight or angled they look like they'd work real nice for an LS engine.

[Nitis]

So looking at your picture it makes sense why the LS won't work in the 67-72 k series

Your crossmemeber is basically straight and perfectly horizontal as ours are more "u" shaped and sits farther back closer to the larger part of the oil pan

So in my uneducated non mechanical opinion this is a viable option. But for the cost of $400 for a dirty dingo is it worth the headache of customizing?


Also in looking at my 72 k10 my crossmember appears to be bolted I. As opposed to riveted does this sound correct?

[BLAZERMAN]

Sorry guys I went back thru the archives and couldn't find where I had posted that article so I found the original magazine and scanned it again.
Hope this helps.

[BigRed76]

Originally Posted by BLAZERMAN

Sorry guys I went back thru the archives and couldn't find where I had posted that article so I found the original magazine and scanned it again.
Hope this helps.

Thank you for finding that

[First c10]

Thank you for the info......I think I am going to try this with an LS build.

[Nitis]

Originally Posted by First c10

Thank you for the info......I think I am going to try this with an LS build.

Yeah buddy thanks for jumping on the gernade!

[First c10]

This is he close up of the stock 67-72 engine crossmember and a 73 up square body

[First c10]

This is what will needed to cut because the 91 burb frame that this came from. It is 5-1/2" and the k20 frame I am using is 5".
The motor mount stand is upside down and bolted to the table so I can cut it tomorrow.

[7dee2]

Looks pretty slick, great info!! I'm sure this will make the LS (or a BB) swap go easy.

[PortalAxls]

Here are some pictures of the crossmember that was in my 67 GMC with the 305 V6. Anyone know if this is the stock crossmember, or a 73-87?

[Nitis]

well to my uneducated eyes it surely looks different than the V8 crossmembers of that vintage

First?

[First c10]

It deffenently is different than the square body v8 cross member. In my earlier picture you can see the stock 67-72 4wd crossmember (black)and the square body( in primer) on top of it. My frame has the bolt holes where your v6 crossmember is bolted. So it maybe a stock v6 crossmember. I am not familiar with the v6 setups. Hopefully someone can chime in. The v6 cross member if stock looks farther forward then my stock one. Below is not a very good picture but you can see the holes in my frame that would accept your v6 crossmember(I think)

[First c10]

Thought I would update this thread a little. I had to cut down the motor mount perches as the sonar frame was 1/2" thicker. So I cut it down and added a piece of 1/4" flat stock. Welded it up. I will post a few more picture.

[First c10]

Cut down.

[First c10]

Ready to clean up with the sanding disc and check fitment