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manual to auto conversion

 
rottnbrat
I love my Chevy Chevette!
Posts: 1
Joined: 05/07
Posted: 05/26/07 06:08 PM

Hi, I have a 57 chevy witha 454 bbc and a muncie 4 speed transmission. I would like to know if anyone can tell me what is involved in converting to an automatic trans. and if the TH400 or the t700r4 is better for a street cruiser.
Thanks  

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Will-#003
I love my Chevy Chevette!
Posts: 2
Joined: 05/07
Posted: 06/02/07 02:08 PM

i had the same problem with my truck.....u would need a new drive shaft to fit the auto tranny....new yolks for the rear end to fit the new shaft...a flex plate to replace your fly wheel...and a tranmission pump to hook up the hydralic lines to...its not an easy job, but *** does it make for a sweet, and valuable, ride.  

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mRHOLLOW45
I love my Chevy Chevette!
Posts: 1
Joined: 06/07
Posted: 06/03/07 05:02 PM

CAN ANYONE TELL WHAT HEADERS TO USE I'M PUTTING A 383 STROKER IN A 1986 MUSTANG HAVING TROUBLE WITH THE STEERING ROD  

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mrpaticular
V-6 Camaros rule!
Posts: 55
Joined: 01/10
Posted: 01/02/10 01:09 PM

On the 4 speed to auto changover there might be some engine changes you need to do. I did the same change on a chevelle and the engine did not want to run right. I had to change the timing some and also adjust the carb idle. The auto puts more drag on the engine and uses about 30 more hp to run it if it is a 400 turbo.  

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tuffnuff
Moderator
Posts: 7841
Joined: 12/09
Posted: 01/02/10 02:43 PM

rottn,,,
your 57 cruiser will be worth less,,, with an automatic.
the TH-400 is a 3 speed auto and much stronger than a 700R4 which is a 4 speed auto
with overdrive.
you will need a 454 flex plate among other things for this swap.
There is a lot of info of these swaps on the web
I would leave it as a 4 speed
Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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mrpaticular
V-6 Camaros rule!
Posts: 55
Joined: 01/10
Posted: 01/02/10 05:11 PM

I would leave it a 4 sp also. People just like to see 4 speeds. Then others do not want the clutch pedal pressure or want the convenience of not shifting. I think it is fun so I have a manual valve body in a 400. It is possible that the trans tunnel might get a little tight since the size of the trans past the bell housing is so much bigger. I know that in the 60's at least that the manfacturer had a different tunnel for the manual trans and the auto. I did the swap on a 69 and there is not even enough room for a trans blanket and if you use an aftermarket floor mounted shifter the cable is tricky to route because of the lack of room.
If your switch is because of clutch pressure did you ever try a Center Force Dual Friction, pretty nice.
I think that I will go back to a Richmond or one of the modern overdrive manuals with a center force in a couple of years myself.  

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tuffnuff
Moderator
Posts: 7841
Joined: 12/09
Posted: 01/02/10 05:24 PM

+1
All 4 Speed muscle cars are worth more than autos
and convertibles more yet,,,
must be a good reason for that
Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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