Auto to 4-speed conversion
Thread Starter
Instructor
Joined: Feb 2013
Posts: 153
Likes: 10
From: Minneapolis
Auto to 4-speed conversion
Have any of you converted an auto to a 4-speed?
I have had my '81 painted and this winter I replaced the interior.....so......I am going to enjoy the car this summer but the only thing that I do not like about it is that it is an auto. I am thinking that this winter I may convert it to a 4-speed if it is not cost prohibitive.
Assuming that I do the work myself, what is the ball park it will cost me to do this and are there any pitfalls to avoid?
I have had my '81 painted and this winter I replaced the interior.....so......I am going to enjoy the car this summer but the only thing that I do not like about it is that it is an auto. I am thinking that this winter I may convert it to a 4-speed if it is not cost prohibitive.
Assuming that I do the work myself, what is the ball park it will cost me to do this and are there any pitfalls to avoid?
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
hardest job is installing the clutch pedal assembly. removing the seat, center console, steering column and the bolts in the wiper cowl (that support the pedals). then you will need to do a little glass work to modify the opening in the floor where the shifter passes into the cabin.
none of these jobs is difficult if you have a little experience.
dropping the trans and installing the bellhousing, z-bar,clutch and trans is straightforward.
biggest pitfall is not rebuilding the trans before you install it. these old muncies have seen a lot of miles. most have worn sliders that cause the trans to pop out of gear. you can do this yourself for about $300.
altogether, less than $2500 for parts. a lot of guys will recommend going to an overdrive trans. add another $2000.
none of these jobs is difficult if you have a little experience.
dropping the trans and installing the bellhousing, z-bar,clutch and trans is straightforward.
biggest pitfall is not rebuilding the trans before you install it. these old muncies have seen a lot of miles. most have worn sliders that cause the trans to pop out of gear. you can do this yourself for about $300.
altogether, less than $2500 for parts. a lot of guys will recommend going to an overdrive trans. add another $2000.
Race Director
Joined: Sep 2005
Posts: 18,640
Likes: 121
From: Farragut,TN
hardest job is installing the clutch pedal assembly. removing the seat, center console, steering column and the bolts in the wiper cowl (that support the pedals). then you will need to do a little glass work to modify the opening in the floor where the shifter passes into the cabin.
none of these jobs is difficult if you have a little experience.
dropping the trans and installing the bellhousing, z-bar,clutch and trans is straightforward.
biggest pitfall is not rebuilding the trans before you install it. these old muncies have seen a lot of miles. most have worn sliders that cause the trans to pop out of gear. you can do this yourself for about $300.
altogether, less than $2500 for parts. a lot of guys will recommend going to an overdrive trans. add another $2000.
none of these jobs is difficult if you have a little experience.
dropping the trans and installing the bellhousing, z-bar,clutch and trans is straightforward.
biggest pitfall is not rebuilding the trans before you install it. these old muncies have seen a lot of miles. most have worn sliders that cause the trans to pop out of gear. you can do this yourself for about $300.
altogether, less than $2500 for parts. a lot of guys will recommend going to an overdrive trans. add another $2000.
Thread Starter
Instructor
Joined: Feb 2013
Posts: 153
Likes: 10
From: Minneapolis
hardest job is installing the clutch pedal assembly. removing the seat, center console, steering column and the bolts in the wiper cowl (that support the pedals). then you will need to do a little glass work to modify the opening in the floor where the shifter passes into the cabin.
none of these jobs is difficult if you have a little experience.
dropping the trans and installing the bellhousing, z-bar,clutch and trans is straightforward.
biggest pitfall is not rebuilding the trans before you install it. these old muncies have seen a lot of miles. most have worn sliders that cause the trans to pop out of gear. you can do this yourself for about $300.
altogether, less than $2500 for parts. a lot of guys will recommend going to an overdrive trans. add another $2000.
none of these jobs is difficult if you have a little experience.
dropping the trans and installing the bellhousing, z-bar,clutch and trans is straightforward.
biggest pitfall is not rebuilding the trans before you install it. these old muncies have seen a lot of miles. most have worn sliders that cause the trans to pop out of gear. you can do this yourself for about $300.
altogether, less than $2500 for parts. a lot of guys will recommend going to an overdrive trans. add another $2000.
I have a buddy that deals with composites professionally, so the cutting the hump and reinforcing the cutout does not worry me.
Am I correct in thinking that the steering wheel has to be removed for access to install the replacement brake and clutch pedals?
Race Director
Joined: Jan 2002
Posts: 11,616
Likes: 350
From: No Where USA
You could pick up the whole setup, soup to nuts for around 1000 to 1500.
I was going to do it last year if I had bought an automatic car. I did some pricing. You may be able to find the parts on the forum or e bay.
I did find a 4 speed and love it.
I was going to do it last year if I had bought an automatic car. I did some pricing. You may be able to find the parts on the forum or e bay.
I did find a 4 speed and love it.
Burning Brakes
Joined: Apr 2007
Posts: 1,039
Likes: 62
From: Kona Hawaii
http://forums.corvetteforum.com/c3-t...am-change.html
Here's my write up...Changed out the crossmember to a G-force 700r4.Fit perfect with just a little trimming and new holes for the trans mount.Go OD and don't look back....
Here's my write up...Changed out the crossmember to a G-force 700r4.Fit perfect with just a little trimming and new holes for the trans mount.Go OD and don't look back....
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Thread Starter
Instructor
Joined: Feb 2013
Posts: 153
Likes: 10
From: Minneapolis
Personally, for me, I think that if I go "auto" to an OD manual transmission this winter, I would try to find a kit that has everything I need.
I am not an expert in transmissions and would be afraid to buy individual parts to make the swap and then the parts do not fit together.
I do have a buddy that is a mechanic by profession that could help me out with obtaining parts and determining what would fit.
How interchangeable are the pedals, Z bar and linkage from other GM cars of the era? We have a few classic car yards in the area, but I do not think that they would have any vettes. I guess that I could also call a few vette salvage yards and see what they would want for the entire set-up.
Thanks for all the help guys. For me this is a big project, buy it will remove the one thing about my vette that I do not like.
I am not an expert in transmissions and would be afraid to buy individual parts to make the swap and then the parts do not fit together.
I do have a buddy that is a mechanic by profession that could help me out with obtaining parts and determining what would fit.
How interchangeable are the pedals, Z bar and linkage from other GM cars of the era? We have a few classic car yards in the area, but I do not think that they would have any vettes. I guess that I could also call a few vette salvage yards and see what they would want for the entire set-up.
Thanks for all the help guys. For me this is a big project, buy it will remove the one thing about my vette that I do not like.
Drifting
Joined: May 2005
Posts: 1,968
Likes: 44
From: East TN
I pulled out the 4 speed in my 80', sold the trans, Hurst shifter, and linkages to fund doing a swap to a T56 6 speed. After selling my parts I spent about another $1200 out of pocket to complete the change over. Total cost I'd say between $2000 to $2500 with a used T56.
http://forums.corvetteforum.com/c3-t...gs-list-7.html
http://forums.corvetteforum.com/c3-t...gs-list-7.html
Racer
Joined: Sep 2002
Posts: 357
Likes: 0
From: Sayville New York
I have just completed the third day of this exact project on my 81. Converting it from an automatic to original 4 spd. I got everything I needed to do the convertion off an 80 from a member on the forum. It is a big job. My car had a lot of sentimental value to me so selling it to buy a 4 spd 81 was not an option. Changing the pedal assembly was a huge deal. The steering wheel has to come out. 80 - 81 had the Z bar bracket bolt to the frame, it's not welded, and the holes are all ready there. Cutting the holes for the shifter and clutch pedal rod are do-able just pain. I hate to sound like a downer, but I would really weigh the options of doing the job or selling it and buying a 4spd car. Just my 2 cents.
Race Director
Joined: Jan 2002
Posts: 11,616
Likes: 350
From: No Where USA
Just buy the parts and get it done with. After a few days work it will be over and you will have what you want. If you want a 4 speed put one in, not an automatic with an overdrive. Let me tell you it is so much more fun to drive these cars with a stick in them. It isn´t hard to do just time consuming. You don´t have to be a rocket scientist to do the job. If you get all the parts together make it the winter project. Or do it on your vacation this summer and it will be done.
Racer
Joined: Sep 2002
Posts: 357
Likes: 0
From: Sayville New York
I have to change the driveshaft. Same length but the u joint is bigger for the 4spd then the driveshaft for the auto. Also these are no big deal but different starter and speedometer cable for the auto is shorter then you will need for the 4spd.
Thread Starter
Instructor
Joined: Feb 2013
Posts: 153
Likes: 10
From: Minneapolis
I have just completed the third day of this exact project on my 81. Converting it from an automatic to original 4 spd. I got everything I needed to do the convertion off an 80 from a member on the forum. It is a big job. My car had a lot of sentimental value to me so selling it to buy a 4 spd 81 was not an option. Changing the pedal assembly was a huge deal. The steering wheel has to come out. 80 - 81 had the Z bar bracket bolt to the frame, it's not welded, and the holes are all ready there. Cutting the holes for the shifter and clutch pedal rod are do-able just pain. I hate to sound like a downer, but I would really weigh the options of doing the job or selling it and buying a 4spd car. Just my 2 cents.
That is not an option for me. Like you this is my baby. I have had it since 1985 (bought it with 27,000 miles) so I know everything that has happened to this car since then and I know the abuse is minimal. It now has about 67,000 miles.
With the time I have put into it the last couple years with paint, rebuilding the engine, rebuilding the brakes and this past winter a complete new interior, I just dont want to sell it.
Racer
Joined: Sep 2002
Posts: 357
Likes: 0
From: Sayville New York
Like I said, I don't want to sound like a downer. Then if you're in the same boat as me I say go for it. I am looking forward to driving it as a stick. I love this car, it used to be my dads and now my kids talk about owning it someday. Everytime I drove it I enjoyed it but it always bothered me it was a sports car and wasn't a stick. So now I am doing something about it. I don't drive the car enough to justify the cost of a 5 or 6 spd. For me the 4spd was affordable and did the job. It is a very do-able job just time consuming. Have patience and it will get done ( at least I hope it will, I am almost there). And when it's done there will be nothing about the car that bothers you. Good luck and feel free to ask me any questions. I am not an expert just doing the same thing on the same car so it is all fresh in my head.
Thread Starter
Instructor
Joined: Feb 2013
Posts: 153
Likes: 10
From: Minneapolis
Like I said, I don't want to sound like a downer. Then if you're in the same boat as me I say go for it. I am looking forward to driving it as a stick. I love this car, it used to be my dads and now my kids talk about owning it someday. Everytime I drove it I enjoyed it but it always bothered me it was a sports car and wasn't a stick. So now I am doing something about it. I don't drive the car enough to justify the cost of a 5 or 6 spd. For me the 4spd was affordable and did the job. It is a very do-able job just time consuming. Have patience and it will get done ( at least I hope it will, I am almost there). And when it's done there will be nothing about the car that bothers you. Good luck and feel free to ask me any questions. I am not an expert just doing the same thing on the same car so it is all fresh in my head.
My thought is to do it over the winter as I have a heated garage. That way I will not get frustrated if I need to take a break from the project.
Racer
Joined: Sep 2002
Posts: 357
Likes: 0
From: Sayville New York
Yes. The zbar bracket gets bolted to the frame. And the holes are all ready in the frame. Just have to clear them out. 30 + years of crud. But yes they are there. Doing it over a winter in a heated garage is the way to go.
Burning Brakes
Joined: Apr 2007
Posts: 1,039
Likes: 62
From: Kona Hawaii
When you decide to do the swap,choose the right trans to match your rear gear ratio.Shoot for a 10:1 first gear start off ratio.My 3.08 rear gear needs a 3.XX 1st gear.I went with a 6spd Richmond which has a 3.28 first gear.3.08 X 3.28= 10.07 just about perfect! To much first gear and your shifting too soon.To little first gear and your gonna be slipping your clutch.
Another reason I like the Richmond 6spd with the 3.08 rear gear is the gear spreads.The gear ratio's keep the rpm's up on upshift's.If you choose the wrong trans you may be disappointed in the performance and end up change rear gears to get the results you want.Added expense...
If you got a big block with loads of torque,well then it's not a big deal cuz you have all that torque to get you rolling along.
Another reason I like the Richmond 6spd with the 3.08 rear gear is the gear spreads.The gear ratio's keep the rpm's up on upshift's.If you choose the wrong trans you may be disappointed in the performance and end up change rear gears to get the results you want.Added expense...
If you got a big block with loads of torque,well then it's not a big deal cuz you have all that torque to get you rolling along.