Transmission Crossmember Question
Thread Starter
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
Transmission Crossmember Question
I have an '81 with a TH350 automatic transmission. I'm going to put headers and the Pypes dual exhaust system on. The exhaust system requires a double hump transmission crossmember. Has anybody used the crossmember from Summit Racing? Your thoughts on it please.
Here is the link to the part...
http://www.summitracing.com/parts/SUM-770321/
Here is the link to the part...
http://www.summitracing.com/parts/SUM-770321/
Melting Slicks
Joined: Apr 2004
Posts: 2,008
Likes: 38
From: Space Coast Gator Territory
That cross member will probably work, but I have no experience with it. I do have experience modifying the stock cross member and it can be done for a lot less money. The exhaust cutouts in the Summit cross member appears to be in the stock porthole location. This will not allow you to straighten out the exhaust in line with the headers/mufflers and straight back. All you need is 4" heavy wall tubing and a welder. If you prefer, a section of box material will resemble the Summit cross member. Get the pieces ready for welding and it wouldn't cost much to have it professionally welded. This is a photo of how I did mine.
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Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
I dont have any experience with that crossmember, but modifying the stock crossmember for exhaust clearance is really not a lot of work.
I bet it wouldn't cost you more than $100 if you paid a weld shop to do it for you.
I bet it wouldn't cost you more than $100 if you paid a weld shop to do it for you.
Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
That cross member will probably work, but I have no experience with it. I do have experience modifying the stock cross member and it can be done for a lot less money. The exhaust cutouts in the Summit cross member appears to be in the stock porthole location. This will not allow you to straighten out the exhaust in line with the headers/mufflers and straight back. All you need is 4" heavy wall tubing and a welder. If you prefer, a section of box material will resemble the Summit cross member. Get the pieces ready for welding and it wouldn't cost much to have it professionally welded. This is a photo of how I did mine.
[IMG][/IMG]
[IMG]
[/IMG]
Thread Starter
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
The '81 crossmember is a different bird than the earlier models that you guys are showing in the pictures. I'm sure that it can be modified but I'd like to reduce the downtime and be able to put all of this together in a day or so. With that in mind... I think fabricating one from scratch might be an idea. Then having it ready to bolt in. OR fabricating pipes from the collectors to the Summit crossmember at a muffler shop.
I'd still like to find someone who purchased the crossmember from Summit and see what the problems were.
@ DRIVESHAFT -is your car an '81? If it is what did you do for a crossmember?
I'd still like to find someone who purchased the crossmember from Summit and see what the problems were.
@ DRIVESHAFT -is your car an '81? If it is what did you do for a crossmember?
Last edited by Street Rat; Jun 26, 2012 at 04:04 PM.
Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
The second pic I posted, right? If so, I get that and have seen fabrications similar and heard of using older xmembers in later cars. But Red 69 seems to have components similiar to both. Did he add the half circle valleys to keep exhaust further from the tranny or to allow pipes to run straight back or something else I haven't thought about...? Just curious.
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Brett Foote
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
The second pic I posted, right? If so, I get that and have seen fabrications similar and heard of using older xmembers in later cars. But Red 69 seems to have components similiar to both. Did he add the half circle valleys to keep exhaust further from the tranny or to allow pipes to run straight back or something else I haven't thought about...? Just curious.
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
Instead of welding in a halved pipe section, I used sheet metal and formed a more gradual recess on the driver's side.
Either way works equally well though.
Last edited by DRIVESHAFT; Jun 26, 2012 at 09:31 PM.
Racer
Joined: Mar 2009
Posts: 394
Likes: 1
From: Everywhere US
The one we used on our 82 a very much like the one at Summit .... love the way it tucked away and looked under the tranny .... and ran the exhaust right out ....
I wouldn't be surprised if it was the same unit with the Summit name on it ...
oh yeah ..... bolted right up .... no mods necessary ... running a 700r4
I wouldn't be surprised if it was the same unit with the Summit name on it ...
oh yeah ..... bolted right up .... no mods necessary ... running a 700r4
Last edited by LastC3AZ; Jun 26, 2012 at 07:41 PM.
Thread Starter
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
@ hal1phx -Yes it is the GForce unit which Summit Racing sells. I see other vendors selling the same unit on auction sites for considerably less money. I don't see your pipes from the collectors through the crossmember openings. I assume that you had a custom system fabricated? Are those headers on the car as well? It really looks great and this picture is a great shot of the installed crossmember. Thanks for sharing the information.
Pro
Joined: Jan 2010
Posts: 533
Likes: 18
From: Boca Raton Florida
Not sure if this is helpful but Bowtie Overdrives sells a tubular crossmember for a 700R4 that bolts to the stock location on your '81. According to their description" "The Th-700R4 is 3.13" longer than your typical short tail housing Th-350..." It may be possible to drill new holes for the TH350 mount. They may even be able to make a mount for your setup. It looks a whole lot lighter than the Summit crossmember and it's $125 cheaper.
http://www.bowtieoverdrives.com/cata...php?ITEMID=115
http://www.bowtieoverdrives.com/cata...php?ITEMID=115
Last edited by Bob Heine; Jun 27, 2012 at 09:42 AM. Reason: I suck at arithmetic and spelling...
Instructor
Joined: Jan 2012
Posts: 111
Likes: 1
From: San Antonio Texas
hal1phx that looks really good! What brand are those headers? They tuck up really nice, my headers hang too low for me they hit on everything.
@street rat that looks like a nice cross member should work for you!
@street rat that looks like a nice cross member should work for you!
Thread Starter
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
Yes the Bow Tie Overdrive crossmember should work with the addition of a plate for the TH350 mount. Or as stated they may be able to weld one on there for me. Now I've got some great options and ideas. I'll post the results when I install something.
Thanks to all who contributed.
Thanks to all who contributed.
Racer
Joined: Mar 2009
Posts: 394
Likes: 1
From: Everywhere US
Thread Starter
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
Update
I decided to pull the factory crossmember out and modify it for a true dual exhaust system. My car is laid up for trailing arm/rear bearing rebuilding so I got bored! 
I will post pictures as soon as I get the crossmember modified.
I will post pictures as soon as I get the crossmember modified.