Manual to Auto
Thread Starter
Burning Brakes
Joined: Sep 2010
Posts: 799
Likes: 26
From: Lexington Park Maryland
Manual to Auto
I am going to make it easy for my wife to cruise around the 72 LT1 by converting it from the 4 speed manual to the 700r4 auto trans. aside from the flywheel, TQ converter and the shifter. Do I need a special lenght drive shaft or can I use the one from the same year with the 350 auto trans? I would like to use the 700R4 for the overdrive but not necessary if it makes the conversion easy. Thank you.
Race Director
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
while some die hards love hunting for gears this is a wonderful upgrade for the c3 you will not regret.
I havent crossed that bridge yet but I am pretty sure you do have to shorten the DS,
The bigger issue in a way is the tranny cross member in manual cars it's welded in and in autos bolt in, so with engine in car no way to install auto trans without modding the crossmember which varies by builder some buy the kits some like me hire it done, if you look at my thread you can see pictures of mine,
https://www.corvetteforum.com/forums...m-project.html
Another big import thing is the cable adjustment it will ruin the tranny fast if not done right...
I havent crossed that bridge yet but I am pretty sure you do have to shorten the DS,
The bigger issue in a way is the tranny cross member in manual cars it's welded in and in autos bolt in, so with engine in car no way to install auto trans without modding the crossmember which varies by builder some buy the kits some like me hire it done, if you look at my thread you can see pictures of mine,
https://www.corvetteforum.com/forums...m-project.html
Another big import thing is the cable adjustment it will ruin the tranny fast if not done right...
Melting Slicks
Joined: Feb 2006
Posts: 3,105
Likes: 96
From: Sunrise FL
I would get lots of opinions on this, esp with the .67 OD of the TH700 and your rear ratio. You don't want to lug an LT1 on the highway, and this is not a trivial swap in general.
Of course keep all old parts for the future
Of course keep all old parts for the future
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,582
Likes: 7,020
From: New Or-leens Loo-z-anna
HERE YA GO............CLICK ON IT.................
https://www.corvetteforum.com/forums...ddly-bits.html
https://www.corvetteforum.com/forums...ddly-bits.html
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,481
From: Southbound
Cruise-In II Veteran
My .02: give serious reconsideration to putting an AT behind an LT-1. All LT-1s were four speed cars. Adding the AT potentially devalues your LT-1.
That said, it's your car and you can certainly make whatever changes you like.
That said, it's your car and you can certainly make whatever changes you like.
Last edited by Easy Mike; Mar 24, 2015 at 08:34 AM.
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Race Director
Joined: Jul 2004
Posts: 12,696
Likes: 329
From: Scottsdale Arizona
Frankly, I think the biggest job is to switch to an auto pedal assembly. Although a common Bubba solution is to hide the clutch pedal under the carpet, this will expose you to scorn and ridicule forever.
The assemblies are not all that hard to find but it's an ungly job with fasteners in ugly places under the dash.
The assemblies are not all that hard to find but it's an ungly job with fasteners in ugly places under the dash.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
Le Mans Master
Joined: May 2006
Posts: 5,814
Likes: 414
From: Pittsburgh suburbs Pa.
The next owner will very much regret the alterations and will probably show that in what he is willing to pay. But if he is planning to keep it forever , then it is his car to do whatever he wants with it. 
Le Mans Master
Joined: May 2006
Posts: 5,814
Likes: 414
From: Pittsburgh suburbs Pa.
The worst part about this is that he will go to all of the trouble of changing this valuable car and if his wife is like most women she won't even care about driving the car. Maybe he is the one that really wants the automatic ? Just a thought !
Team Owner
Joined: Jun 2000
Posts: 38,923
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From: Southbound
Cruise-In II Veteran
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
Two issues I can think of are the cross member and rpm range where the LT1 begins to develop some torque. Will an LT1 perform well at low RPM with an automatic? Would a torque converter which locks at higher rpm be required? How original is the car. Hacking the cross member may reduce the future value considerably since it would be difficult to reverse.
Thread Starter
Burning Brakes
Joined: Sep 2010
Posts: 799
Likes: 26
From: Lexington Park Maryland
Thank you everyone for your inputs. Yes, the thought of lower value has crossed my mind. We have two corvette, I enjoy the C7, but when we (my wife and I) want to cruise together she does not like the C7 due the power. She enjoys the C3, hence I would like to convert it so she can drive.
The other consideration is sell this one and find her an automatic C3 (must be 70-72 year).
I enjoy driving the car as it is...
The other consideration is sell this one and find her an automatic C3 (must be 70-72 year).
I enjoy driving the car as it is...
Le Mans Master
Joined: Feb 2011
Posts: 5,943
Likes: 61
From: Southern NH
Thank you everyone for your inputs. Yes, the thought of lower value has crossed my mind. We have two corvette, I enjoy the C7, but when we (my wife and I) want to cruise together she does not like the C7 due the power. She enjoys the C3, hence I would like to convert it so she can drive.
The other consideration is sell this one and find her an automatic C3 (must be 70-72 year).
I enjoy driving the car as it is...
The other consideration is sell this one and find her an automatic C3 (must be 70-72 year).
I enjoy driving the car as it is...
I think i'd trust her more with the C7 though. much easier car to drive even with all the power.
Racer
Joined: Jan 2013
Posts: 326
Likes: 7
Frankly, I think the biggest job is to switch to an auto pedal assembly. Although a common Bubba solution is to hide the clutch pedal under the carpet, this will expose you to scorn and ridicule forever.
The assemblies are not all that hard to find but it's an ungly job with fasteners in ugly places under the dash.
The assemblies are not all that hard to find but it's an ungly job with fasteners in ugly places under the dash.