Can someone explain why....
Thread Starter
Burning Brakes
Joined: Oct 2022
Posts: 1,063
Likes: 170
From: Buckeye Lake, OH
Can someone explain why....
The manual transmission cross members were welded, when the auto-transmissions were bolted in?
Why the difference between the two? I just don't 'get' it.
Why the difference between the two? I just don't 'get' it.
Race Director
Joined: Mar 2017
Posts: 11,960
Likes: 4,518
From: Virginia
The welded frames are stronger.
80-82 frames are made out of slightly thinner material (part of taking 250 lbs of weight off the car in the partial redesign), yet all frames came with bolt-in transmission crossmembers.
C3s were assembled by dropping the body onto the completed chassis (with engine, transmission, and drivetrain already in place), so they never had to do the job on jackstands in a gravel driveway.
80-82 frames are made out of slightly thinner material (part of taking 250 lbs of weight off the car in the partial redesign), yet all frames came with bolt-in transmission crossmembers.
C3s were assembled by dropping the body onto the completed chassis (with engine, transmission, and drivetrain already in place), so they never had to do the job on jackstands in a gravel driveway.
Race Director
Joined: Mar 2016
Posts: 14,428
Likes: 8,232
From: Napa Valley California
When you find the answer to that question, then maybe you can tell us why GM welded the clutch Z Bar bracket onto the 4 speed frames but they didn’t weld it on the automatic frames.
Race Director
Joined: Mar 2017
Posts: 11,960
Likes: 4,518
From: Virginia
Melting Slicks
Joined: Jan 2012
Posts: 3,041
Likes: 505
From: myrtle beach sc
Army
68 -72 Corvettes were road raced extensively back in the day. They are the only Vettes with solid body mounts because of this fact. That is why the four speed frames had the welded crossmember to cut down frame twisting. Also the automatic transmission is a lot larger and needed the removable crossmember. So now you know why the welded crossmember is there. Lou.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
When you pull the automatics out, the built-in bellhousing had to go with the tranny = extra long to clear the crossmember.
When you pull a 4 speed, the bellhousing stays with the engine = shorter, to clear the crossmember.
So its a weight and length thing.
When you pull a 4 speed, the bellhousing stays with the engine = shorter, to clear the crossmember.
So its a weight and length thing.
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