Difference in Auto/4Spd 1978 tranmission tunnel?
Can anyone tell me if the transmission tunnel on a 1978 automatic is different than a 4 speed car? The replacement boot for a 4 speed does not appear to fit properly over the transmission tunnel 'dent' for the shifter of an original auto trans. Any pictures of a 4 speed tunnel and boot would be appreciated. Thanks in advance.
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Re: Difference in Auto/4Spd 1978 tranmission tunnel?
Hi George,
Here are a picture from below and above.
I believe the 4-speed boot is the same for 68-82 that were available with 4-speed transmissions.
Hope these are a help.
Regards,
Alan
DSC_0128.jpgLast edited by Alan S.; October 28, 2014, 05:53 PM.71 Coupe, 350/270, 4 speed
Mason Dixon Chapter
Chapter Top Flight October 2011 -
Re: Difference in Auto/4Spd 1978 tranmission tunnel?
your tunnel looks flat. the 78 auto trans tunnel has a 1" deep 4"x5" 'dent'. attempting to replace auto with 4 speed and the boot looks like yours but doesn't fit very well over the 'dent'... thanks for the picComment
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Re: Difference in Auto/4Spd 1978 tranmission tunnel?
Hi George,
I added another picture to the first post with a view from below.
Regards,
Alan71 Coupe, 350/270, 4 speed
Mason Dixon Chapter
Chapter Top Flight October 2011Comment
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Tom Russo
78 SA NCRS 5 Star Bowtie78 Pace Car L82 M2100 MY/TR/ConvComment
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Re: Difference in Auto/4Spd 1978 tranmission tunnel?
Tom------
The 1978 PRODUCTION underbody panel for automatic trans applications was GM #468135. For 4 speed applications it was GM #468136. The latter was never available in SERVICE while the 468135 SERVICED (with other GM-specified mods) both auto and 4 speed applications. The 468135 was discontinued in February, 1985 and replaced by GM #14038269 which was the PRODUCTION and SERVICE panel for 1982 Corvettes.
1979-82 used panels unique to each year. However, the same pattern was followed. Namely, there were different panels for auto and 4 speed for each year (except 82, of course, which was auto only) but only the auto panel was available in SERVICE. The 1982 panel, GM #14038269, ultimately became the SERVICE panel for all 1978-82 Corvettes and was finally discontinued without supercession in November, 1988.
What was the difference between the auto and 4 speed panels? I don't know, but I expect that George has identified at least one of the differences.In Appreciation of John HinckleyComment
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Re: Difference in Auto/4Spd 1978 tranmission tunnel?
Thanks to all for the comments/pics. Guess will have to do some boot modification/fabrication on this swap.Comment
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Re: Difference in Auto/4Spd 1978 tranmission tunnel?
George
I actually have a 78 auto and a 78 four-speed sitting in my garage...but I am not sure what I would be looking for and I couldn't tell from the photos. The four-speed car has the console removed so I can access it from the top. Point me in a direction and I'll see if I can come up with something instructive.Tom Russo
78 SA NCRS 5 Star Bowtie78 Pace Car L82 M2100 MY/TR/ConvComment
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Re: Difference in Auto/4Spd 1978 tranmission tunnel?
Tom,
Friend has original 78 pace 4 speed car that was totaled from behind while his wife was driving. ( thank God she was ok). He purchased a 78 pace body that has auto tunnel. They are different but can not tell difference for making a cut in the tunnel and placement of a boot. If you have pics of both it would be helpful.. The wreck occurred about 10 years ago, and as a restorer he has done other's cars, but has a break from mine as I have had to order another block - SEE MY HARD BLOK POST for the gory details!!
Thanks, GeorgesComment
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