Re: Double Hump Cross Member

Re: Double Hump Cross Member · by crice63 Sun Sep 25, 2016 2:31 pm

Thanks for those pics. The 200-4R three holes? Or are they for adjusting? I had determined from my stock single hump that my center mount hole was offset to the passenger side by .25". Is that accurate as far as everyone knows--the drive train is off to the side a little? I used a Crown Vic x-member, and after cuts it matched my stock in terms of where the holes were. But my headers are crowded on the passenger side, sitting up against the frame a little bit. I was going to shim it up a half inch but when I raised it up it really didn't get off the frame. So now I'm wondering if that off-center bit was not correct.

Re: Double Hump Cross Member · by BAS-Sr Sun Sep 25, 2016 4:00 pm

crice63 wrote:Thanks for those pics. The 200-4R three holes? Or are they for adjusting? I had determined from my stock single hump that my center mount hole was offset to the passenger side by .25". Is that accurate as far as everyone knows--the drive train is off to the side a little? I used a Crown Vic x-member, and after cuts it matched my stock in terms of where the holes were. But my headers are crowded on the passenger side, sitting up against the frame a little bit. I was going to shim it up a half inch but when I raised it up it really didn't get off the frame. So now I'm wondering if that off-center bit was not correct.

The 200-4R trans is a single bolt mount for the cross member, same as the T-350.

The passenger side header is real tight near the frame, does not hit or rattle, just REAL tight. The Patriot headers seem nice so far, real PITA to get in though.

Re: Double Hump Cross Member · by Shaunaconda Sun Sep 25, 2016 7:19 pm

Mcarlo77 wrote:
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).

I guess I haven't logged in in awhile but I've been around just about every day. Anyway I got the crossmember from you Steve. Wasn't it from an El Camino?

Re: Double Hump Cross Member · by Mcarlo77 Sun Sep 25, 2016 10:21 pm

Ha...I'd forgotten you had bought one from me! I've pulled and sold several of both and have no specific recollection...but, would not have sent you an El Camino one for your Laguna. They just won't fit.

I trust you're still enjoying the Laguna! If I recall, it's the same Orange Poly color as mine?

Miracle! · by BAS-Sr Sat Oct 01, 2016 12:40 pm

Well, Miracles do HAPPEN!

I had the time this morning, so I put the '75 el Camino up on my lift, first thing I did was to put the new double hump cross member up below it, low and behold it looked like it was going to go right in WITHOUT having to modify it for the 200-4R trans! :-)

I dropped the exhaust, took the old one out, put the new one in and it bolted right up, no need for modifying and all the bolt holes to the frame and the 200-4R trans lined right up! Much better fit than the single hump cross member, the humps in the double hump are nicely situated for a new exhaust system! :-)

MIRACLE! and the new cross member only cost me $40!

Re: Double Hump Cross Member · by crice63 Sun Oct 02, 2016 10:11 am

Well that was a good find. I have not found one yet, though I have one from A 73 Laguna if anyone wishes to trade. A guy did post locally a 200-4R so I may go look at it. He claims it is a stage 2 but he looks like a racer, may be really beat on.

Reviving this thread · by relic7680 Wed Jan 18, 2017 11:24 pm

I have the 6273808 dual exhaust crossmember. I got it off EBay about ten years ago wanting to use it on my '76 Sprint. However, I discovered after finally digging it out the other day that it is too narrow for the frame on my car.

The GM parts catalog tells the story....kind of. Says it's for 73-74, but if I recall correctly, the OP said he put one on his '75 El Camino? Was there a frame change for the '76 model year?

My 6273808 measures 46.5" long and the 348094 single unit off my '76 EC parts car is 52.5". Was there a 52.5" crossmember with dual exhaust at all? I know it wasn't an option in 76-77.... Double Hump Cross Member - Page 2 Img_4514

Double Hump Cross Member - Page 2 Img_4514

Re: Double Hump Cross Member · by relic7680 Wed Jan 18, 2017 11:26 pm

Re: Double Hump Cross Member · by Mcarlo77 Thu Jan 19, 2017 1:26 am

You can't compare lengths of single exhaust '75-'77 to dual exhaust '73/'74 because they mount differently. Duals run straight across and singles mount at an angle. If you're trying to use the same mounting holes with the dual as were used on the single, it's going to be too short. There are other holes in the frame you use for the dual. You have the correct dual cross-member for an Elkie/Sprint.

Re: Double Hump Cross Member · by crice63 Thu Jan 19, 2017 5:07 pm

I share MCarlo's take on this. There are 2 sets of mounting holes in the flange on the frame that the Xmember mounts on. The single hump xmember mounts at an angle. the 73-73 dual hump members mount straight across, and should fit the factory holes, either the front set or the back set depending on the engine/tranny size. I don't think the frame changes between 75 and 76 at least, and know it didn't between 74-75 at that spot, so an Xmember from the 74 should fit my 75. If you don't want to use yours I'd be willing to take a chance on it.

Re: Double Hump Cross Member · by BAS-Sr Thu Jan 19, 2017 5:55 pm

Mcarlo77 wrote:You can't compare lengths of single exhaust '75-'77 to dual exhaust '73/'74 because they mount differently. Duals run straight across and singles mount at an angle. If you're trying to use the same mounting holes with the dual as were used on the single, it's going to be too short. There are other holes in the frame you use for the dual. You have the correct dual cross-member for an Elkie/Sprint.

crice63 wrote:I share MCarlo's take on this. There are 2 sets of mounting holes in the flange on the frame that the Xmember mounts on. The single hump xmember mounts at an angle. the 73-73 dual hump members mount straight across, and should fit the factory holes, either the front set or the back set depending on the engine/tranny size. I don't think the frame changes between 75 and 76 at least, and know it didn't between 74-75 at that spot, so an Xmember from the 74 should fit my 75. If you don't want to use yours I'd be willing to take a chance on it.

I agree to a point....what I did was measure the distance between the frame mounting holes, found that both the single hump and the double hump work while mounting differently....

I have the original single hump and a custom built double hump one still hanging around my garage, if anyone is interested:

http://cnj.craigslist.org/pts/5960065621.html

http://cnj.craigslist.org/pts/5960065720.html

Re: Double Hump Cross Member · by Limey SE Thu Jan 19, 2017 8:23 pm

Be prepared to sell that Compucar Very fast (custom one) I am putting on my face book Groups

Re: Double Hump Cross Member · by g3chevy / Mr Pontiac Thu Jan 19, 2017 11:22 pm

All the 76 and 77 El Camino/Sprints I've owned or personally looked at have a channeled frame under the rockers. And all of the 73-75's I've seen have boxed frames as does my current 75 SS El Camino with factory 454/400 combo. I first discovered this back in 89 when I was doing a crossmember swap on my 76 Camino. I purchased a dual hump crossmember from a 73 SS El Camino with a 350/350 setup and it was about 6 inches too narrow. Here are some pics for reference.

Double Hump Cross Member - Page 2 Photo011

Double Hump Cross Member - Page 2 Photo011

Double Hump Cross Member - Page 2 Photo010

76-77 frame difference · by relic7680 Fri Jan 20, 2017 1:26 am

g3chevy wrote:All the 76 and 77 El Camino/Sprints I've owned or personally looked at have a channeled frame under the rockers. And all of the 73-75's I've seen have boxed frames as does my current 75 SS El Camino with factory 454/400 combo. I first discovered this back in 89 when I was doing a crossmember swap on my 76 Camino. I purchased a dual hump crossmember from a 73 SS El Camino with a 350/350 setup and it was about 6 inches too narrow. Here are some pics for reference.

YES. This is what I found. My 73-74 crossmember is 6" too narrow, despite another set of mounting holes being in the frame behind the ones used for my single exhaust unit.

Dual Exhaust Crossmember · by relic7680 Fri Jan 20, 2017 1:28 am

crice63 wrote:I share MCarlo's take on this. There are 2 sets of mounting holes in the flange on the frame that the Xmember mounts on. The single hump xmember mounts at an angle. the 73-73 dual hump members mount straight across, and should fit the factory holes, either the front set or the back set depending on the engine/tranny size. I don't think the frame changes between 75 and 76 at least, and know it didn't between 74-75 at that spot, so an Xmember from the 74 should fit my 75. If you don't want to use yours I'd be willing to take a chance on it.

It's for sale as of right now......PM me if you still have interest.

Re: Double Hump Cross Member · by g3chevy / Mr Pontiac Sat Jan 28, 2017 2:58 pm

Here's a pic of a single hump crossmember compared to a double hump. Both are approximately 52" from bolt holes to bolt holes. So these would not fit 73-75 El Caminos. They would require a 46.5" crossmember due to the boxed frames. From the information I've researched in factory manuals and such indicate the 75 Camino was the only year they did a 46.5" single hump crossmember. This of course is a result of the government regulations that all passenger vehicles be equipped with a catalytic converter.

Double Hump Cross Member - Page 2 Crossm10

Double Hump Cross Member - Page 2 Crossm10

Double Hump Cross Member - Page 2 Crossm11

Re: Double Hump Cross Member · by crice63 Sat Jan 28, 2017 4:20 pm

Nice pics. I didn't realize that SH xmember rusting away in my yard was so rare.

Re: Double Hump Cross Member · by pila Sat Jan 28, 2017 11:23 pm

The Elco frame is different, boxed kinda I believe, compared to the Chevelle ? I'm under my Elco all the tmie but not the Malibu !
The shorter member may be Elco only ?
My notes say it's 54 1/2 ", but I didn't note if it's Elco or Chevelle Smile

Re: Double Hump Cross Member · by relic7680 Thu Feb 02, 2017 6:14 pm

This has been a very informative thread. Maybe a STICKY?

Re: Double Hump Cross Member · by fasrnur Thu Feb 02, 2017 6:21 pm

It may not be the prettiest thing relic7680, but this is what I did to mine. Didn't cost me much either. Very Happy

http://www.g3gm.com/t10383-dual-exhaust-crossmember?highlight=crossmember

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