700R4 in a 78???
Thread Starter
Intermediate
Joined: Nov 2001
Posts: 35
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From: Colorado Springs CO
700R4 in a 78???
Has anyone ever put a 700R4 4 speed automatic into a 78 SA? How tough is it? What kind of modifications need to be done? I heard that you have to re-weld the crossmember?
I have a 3 speed tranny now and I have 373 gears in the rear end. When I am on the highway doing about 80MPH, I am pulling about 4000 rpm. It is good for around town, but for cruzing, it has to be hard on the ZZ4 motor.
I am just wondering if I should go to a 700R4 or drop the rear end gears down a little bit?
Any help would be appreciated. :smash:
I have a 3 speed tranny now and I have 373 gears in the rear end. When I am on the highway doing about 80MPH, I am pulling about 4000 rpm. It is good for around town, but for cruzing, it has to be hard on the ZZ4 motor.
I am just wondering if I should go to a 700R4 or drop the rear end gears down a little bit?
Any help would be appreciated. :smash:
Instructor
Joined: Oct 2001
Posts: 155
Likes: 0
From: Corrales, NM
Re: 700R4 in a 78??? (bryan78nCO)
Bryan,
This is a relatively easily swap and well worth it. I originally had the same transmission as you and the same gearingm in my 1980. I always felt I was winding the engine up too high. With the 700R-4, everything works like it should. Its a great improvement! The engine runs cooler, quiter and you get better gas mileage. The swap has been well documented so check the archives.
Good Luck!
Ken
This is a relatively easily swap and well worth it. I originally had the same transmission as you and the same gearingm in my 1980. I always felt I was winding the engine up too high. With the 700R-4, everything works like it should. Its a great improvement! The engine runs cooler, quiter and you get better gas mileage. The swap has been well documented so check the archives.
Good Luck!
Ken
Thread Starter
Intermediate
Joined: Nov 2001
Posts: 35
Likes: 0
From: Colorado Springs CO
Re: 700R4 in a 78??? (ENCHANTMENT)
Are there certain types of 700R-4's to get for the corvette or are all of the 700R-4's the same? What about putting it behind a ZZ4? I have heard that the stock 700R-4 will break fairly easy if it is bolted up behind any type of performance motor? any truth to this?
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: 700R4 in a 78??? (bryan78nCO)
What you want is a 700r4 from '88 up in years....and from a truck or impala maybe....you want a standard tail shaft, not a C4 vette thing....
you also want the Trans-Go shift kit...NOT something else...
the later trannies should come with all the late fixes from GM...the earlier ones are full of bugs cost a fortune to update....get a good late core to start with....rebuild kits are only about 250 bux...plus 150 bux for a torque converter....plus 70 for the kickdown cable...plus shorten driveshaft about 80 bux....plus core charge...150 bux.....as you have no exchange....
jGENE
you also want the Trans-Go shift kit...NOT something else...
the later trannies should come with all the late fixes from GM...the earlier ones are full of bugs cost a fortune to update....get a good late core to start with....rebuild kits are only about 250 bux...plus 150 bux for a torque converter....plus 70 for the kickdown cable...plus shorten driveshaft about 80 bux....plus core charge...150 bux.....as you have no exchange....
jGENE
