Double Hump Cross Member

Double Hump Cross Member · by BAS-Sr Fri Sep 23, 2016 6:54 am

I picked up a trans cross member for my '75 el Camino, its double hump for dual exhaust, looks like it might do the job, has 6273808DS stamped on the trans mounting pad. I have a 200-4R installed, so before I go through all the effort of taking my single hump out, modifying the trans mount on the double hump, would like to see if anyone has a pic of a double hump cross member or knows what the number on it shows it is for?

Re: Double Hump Cross Member · by Joe73 Fri Sep 23, 2016 6:59 am

i don't know what the.number.indicates, but if.its a.double.bump from an do Camino it will fit. Malibu crossmember will not work.

Re: Double Hump Cross Member · by Limey SE Fri Sep 23, 2016 7:41 am

Joe is right If its from an EL Camino it will fit..... You may have to double check the fitment of the 200 4 R tans bolt for the cross member as they were only designed for the th350 and th400 to bolt up SO may have to finagle the fitment a little bit

Re: Double Hump Cross Member · by 1973montec Fri Sep 23, 2016 1:07 pm

I think 200 and 350s are the same case. but ive never put them side by side..

Re: Double Hump Cross Member · by Limey SE Fri Sep 23, 2016 3:33 pm

Re: Double Hump Cross Member · by fasrnur Fri Sep 23, 2016 7:38 pm

This might help with your questions.

http://www.tciauto.com/tc/trans-dim/

Re: Double Hump Cross Member · by BAS-Sr Fri Sep 23, 2016 8:55 pm

Well, thanks for the info, but my question is not about the trans, and I also noted that I have to modify the cross member trans mount as I did with the stock CAT exhaust, but wondering how I can identify the cross member, possibly by the number on it (6273808DS), but you say that it will "ONLY" work if out of an el Camino, not a Malibu? Why a "Malibu"? '73 thru '77's were not Malibu's (were they not), but Chevelle's and Laguna S3's?

What's different on the '75 frame (side to side) for an el Camino oppossed to Chevelle?

Re: Double Hump Cross Member · by Mcarlo77 Fri Sep 23, 2016 9:15 pm

Chevelle/Malibu/Monte cross member will measure around 52 1/2" O.A.L. El Caminos are about 1 3/4" shorter because of the boxed frame. BTW...that is a GM part number stamped on it.

Re: Double Hump Cross Member · by Joe73 Fri Sep 23, 2016 10:35 pm

Malibu were produced also produced 73 through 77. Depends on option package. 73 even had a "deluxe" model with its emblem on the fender instead of the Malibu name plate.

Re: Double Hump Cross Member · by 77camino Fri Sep 23, 2016 10:38 pm

Just as an option for someone looking for a one. Does a wagon have the same cross member as an el camino?

Re: Double Hump Cross Member · by Mcarlo77 Fri Sep 23, 2016 10:56 pm

I believe your pt# 6273808 IS for '73/'74 El Camino. I also believe I've read where the station wagons have the boxed frame...so, they'd use the same crossmember, too.

Re: Double Hump Cross Member · by fasrnur Sat Sep 24, 2016 12:18 am

This is what Mcarlo77 is refering to about the frames and why the Chevellle/Malibu crossmember might not the Elky frame.

https://www.g3gm.com/t8292p50-75-el-camino-project

https://www.g3gm.com/t7483-hawk03-redo

Re: Double Hump Cross Member · by pila Sat Sep 24, 2016 1:01 am

I just looked in my notes, and the one I measured for my Elco is 54 1/2 inches between the bolt hole centers, on the ends. And the distance between the centers of the two "humps' is 19 1/2 inches
So there would be another approx one inch on each end beyond the mounting holes....

Re: Double Hump Cross Member · by Mcarlo77 Sat Sep 24, 2016 10:49 am

Don't know about your measurements, Bill...but, factory dual humps for these "A" bodies are not that long. Here's an old post confirming mine and another member's measurements for both Chevelle/Malibu and Sprint:

https://www.g3gm.com/t4121-transmission-crossmember?highlight=crossmember

Re: Double Hump Cross Member · by BAS-Sr Sat Sep 24, 2016 1:28 pm

Mcarlo77 wrote:Chevelle/Malibu/Monte cross member will measure around 52 1/2" O.A.L. El Caminos are about 1 3/4" shorter because of the boxed frame. BTW...that is a GM part number stamped on it.

Actually, the one in there now (non-double hump) is ~48" and the one I got is the same, ~48", so I would have to believe that the double hump one I got is for an el Camino. Also, guy I bought it from only has el Camino's (has a '73 with a 502 in it).

Re: Double Hump Cross Member · by BAS-Sr Sat Sep 24, 2016 1:32 pm

Mcarlo77 wrote:Don't know about your measurements, Bill...but, factory dual humps for these "A" bodies are not that long. Here's an old post confirming mine and another member's measurements for both Chevelle/Malibu and Sprint:

https://www.g3gm.com/t4121-transmission-crossmember?highlight=crossmember

Well looks like the odds are good that the new double hump one should do the trick, so it's a good bet for me to proceed with the modifying it for the 200-4R trans, have done 2 already so I am getting good at modifying the mount! :-)

Re: Double Hump Cross Member · by Mcarlo77 Sat Sep 24, 2016 2:47 pm

You're good to go. My statement of the El Caminos being 1 3/4" shorter is incorrect. Closer to 4".

Re: Double Hump Cross Member · by pila Sat Sep 24, 2016 11:40 pm

Maybe my notes are wrong (?) Now I'll have to measure mine next time I'm under there ! Very Happy

Re: Double Hump Cross Member · by Shaunaconda Sun Sep 25, 2016 12:32 am

If I remember right I put a dual hump cross member from an El Camino on a '76 Laguna that was single exhaust with a cat. Easy bolt on, the frame already had the mounting holes.

Re: Double Hump Cross Member · by Limey SE Sun Sep 25, 2016 1:10 am

Shaunaconda wrote:If I remember right

WOW Heres a Blast from the past Good to see your live and well LOL

Re: Double Hump Cross Member · by crice63 Sun Sep 25, 2016 2:23 am

My measurements were: on stock single hump xmember 47" edge to edge 45.5" between holes. Hump side has slots to allow for fitment. From mount slot center to hole center: hump side is 22.5", driver side is 23". Width between holes on same side is 2.5" center to center.
On frame, the holes are 45.5" and the whole space available is 49", though it's hard to tell exactly where the frame box starts to flatten.

BAS, I hope you show us how you are altering your platform. I hope to find a 200-4R and make the swap some day.

Re: Double Hump Cross Member · by BAS-Sr Sun Sep 25, 2016 6:33 am

crice63 wrote:My measurements were: on stock single hump xmember 47" edge to edge 45.5" between holes. Hump side has slots to allow for fitment. From mount slot center to hole center: hump side is 22.5", driver side is 23". Width between holes on same side is 2.5" center to center.
On frame, the holes are 45.5" and the whole space available is 49", though it's hard to tell exactly where the frame box starts to flatten.

BAS, I hope you show us how you are altering your platform. I hope to find a 200-4R and make the swap some day.

I did the conversion in my '87 el Camino, originally had a Turbo 200 in it, I put the 200-4R in it, which required the cross member trans mount to be modified. Then when I did the conversion from Turbo 350 to the 200-4R in my '75 el Camino SS, had to do the same modification on the single hump cross member.

I'll take pictures of the before and after on the double hump. How do we attache/insert pictures on this forum. Some of the other forums I am on allow you to attach a few pictures?

Maybe I can just post them to my PhotoBucket account and just post the URL here?

Re: Double Hump Cross Member · by crice63 Sun Sep 25, 2016 10:22 am

That's how I've been doing my pics here.

Re: Double Hump Cross Member · by Mcarlo77 Sun Sep 25, 2016 11:02 am

Shaunaconda wrote:If I remember right I put a dual hump cross member from an El Camino on a '76 Laguna that was single exhaust with a cat. Easy bolt on, the frame already had the mounting holes.

Also, good to hear from you again, Shaun! But, I don't think this could have been possible without some bracket extensions as the distance between inner edges of the rails on a Laguna is about 48"...exceeding the overall measurement of an El Camino crossmember (around 47 1/2" lg).

Re: Double Hump Cross Member · by BAS-Sr Sun Sep 25, 2016 11:54 am

Here are some pictures of the stock double hump cross member and an aftermarket one that I got from the same guy that he had made up for his '73 el Camino SS with the 502 in it.......

https://s308.photobucket.com/user/BSarte/library/Car%20Collection/Cross%20Members

Let me know if you can't see the pictures..........

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