LS swap trans crossmember
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From: Hou. TX
Car: 86 TA, 91 B4C
Engine: 5.3, 4.8
Transmission: 4L80 4000, T56
Axle/Gears: 4.30 M12, 23.42 10 bolt
LS swap trans crossmember
What should i di, the Spohn SUCKs and my exhaust scrapes everywhere, the torque arm is set up to mount to the trans crossmember, so any ideas? Mount it to the frame with some custom fabbing and a custom trans crossmember? Only idea i have.
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iTrader: (2)
Joined: Dec 2006
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From: Hou. TX
Car: 86 TA, 91 B4C
Engine: 5.3, 4.8
Transmission: 4L80 4000, T56
Axle/Gears: 4.30 M12, 23.42 10 bolt
Re: LS swap trans crossmember
Yea, but there is still the problem of where the TQ arm attaches right where you need a hump on the driver side.
Re: LS swap trans crossmember
You shouldnt need to tuck it that high


Mine is raised roughly 1.5" and Ive never had a ground clearance problem. My LM1 resonator is the lowest point in the exhaust and its only touched in severe bumps


Mine is raised roughly 1.5" and Ive never had a ground clearance problem. My LM1 resonator is the lowest point in the exhaust and its only touched in severe bumps
Joined: Mar 2000
Posts: 43,187
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
His torque arm mounts to the crossmember, right where you need the hump.
So far, it doesn't appear that both issues of humps for exhaust clearance and mounting the torque arm to the crossmember have been addressed. An alternative is to use a torque arm that mounts to its own crossmember, but if you already have a crossmember-mounted Spohn torque arm, you're hosed without major modifications.
So far, it doesn't appear that both issues of humps for exhaust clearance and mounting the torque arm to the crossmember have been addressed. An alternative is to use a torque arm that mounts to its own crossmember, but if you already have a crossmember-mounted Spohn torque arm, you're hosed without major modifications.
Re: LS swap trans crossmember
I do, didnt see a need for two. A dab of blue locktite on the bolts and it wont be coming back out short of a breaker bar. I hung my weight from the crossmember and it didnt budge, so strength isnt an issue
Certain reason I need all 4?
Certain reason I need all 4?
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Thread Starter
Supreme Member
iTrader: (2)
Joined: Dec 2006
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From: Hou. TX
Car: 86 TA, 91 B4C
Engine: 5.3, 4.8
Transmission: 4L80 4000, T56
Axle/Gears: 4.30 M12, 23.42 10 bolt
Re: LS swap trans crossmember
I only see a need for 4 if you are like me and want to beat it to death at the drag strip and EVERY time you drive it. I hacked a stock trans crossmember and it holds fine so i am sure that piece does very well.
I will just have to see what i can do to mod the spohn piece, i have cut it a bit, but i am sure i can come up with something, just the damn powder coating that gets in the way.
I will just have to see what i can do to mod the spohn piece, i have cut it a bit, but i am sure i can come up with something, just the damn powder coating that gets in the way.
Joined: Mar 2000
Posts: 43,187
Likes: 45
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
That frame rail material is pretty thin. In 1999 when I did the original V6 to V8 swap, I had to drill the back two bolt holes in my '82 (short tranny/longer crossmember mounted farther forward than the later years). I put a flat washer under each nut. In 2005 when I pulled engine/tranny for the 350 upgrade, the nuts had bent the washers and had distorted the actual frame rail.
I had to drill the same holes for my current LS1/T56 project, this time I put a piece of strap steel inside the frame rail and put the nuts on top of it. Much better support.
I'd suggest using all 4 bolts.
I had to drill the same holes for my current LS1/T56 project, this time I put a piece of strap steel inside the frame rail and put the nuts on top of it. Much better support.
I'd suggest using all 4 bolts.
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