3 speed auto to 4 speed auto upgrade.

[Flared69]

Hello people,

My father bought a 1980 3 speed auto a while back, and he'd really like to upgrade to a 4 speed auto. Does anyone have any guides/information regarding this issue? I have searched this forum and google but to no avail.

Any help is appreciated

 

[GerryLP]

You can compare dimensions on trannys here: http://www.tciauto.com/tech_info/trans_dims.htm

A cool calculator that compares shift points vs MPH among three other trannys when entering your current tranny model: http://www.700r4.com/speedoCalc/rpmgearscalc.shtml

Tranny swap galore: http://www.chevyhiperformance.com/techarticles/46140/index.html

Good info for starting...

 

[Flared69]

cheers mate.

appreciated

 

[BLACKDOG]

Flared69 - have your Dad look into the 200-4/R. This is the swap I went with last May in my '80. Having that overdrive makes a nice difference when you are cruzin !!

With the 200-4/R, you won't need to cut down the driveshaft like you will with the 700R4.

Good luck !!

 

[Robin7TFour]

GREETINGS , what is the differnces in the 200-2/r and the 700-4r. i would prefer a manual 4 speed ,but the auto swap would be cheaper..

ROBIN

 

[AKRAY4PLAY]

Robin,
there are two main differences in the 200R4 and 700R4. first the length is different, as stated above. second the internals are slightly different as well. the 200 is stronger than the 700, but the 700 has a deeper first gear. the 700 works better for low powered motors, 200 for medium power and a TH400 with GearVendors overdrive for high hp. i would not run any more than 450 ft/lbs in to a 700R4, it just won't last. 200's and 700's are about $1700 for the conversion and a GV is $2200. Brian

 

[Robin7TFour]

BRIAN, thanks for that explaination. until i dyno my motor i can only guess at the h/p. based on the equipment i think it's in the 370 range. so when the t/h goes bad, i know the 200 is the better choice.unless i make a killer deal on a manual set-up.

thanks again..

BUBBA ...the shade tree scientist

 

[AKRAY4PLAY]

what's your combo?? we can figure it out to within 10% before you start it. if it is going to be a few months before you are looking at tranny time, i will have some step by step install pics and info for the GV overdrive kit on my TH400. it will have to wait until June/July time before the roads clear enough for me to drive the car. Alaska does have a couple draw backs, but i still love it. Brian

 

[MaineShark]

The 200-4R also has closer gear ratios than the 700-4R, which is always a good thing

Joe

 

[drags1998]

My vote would be for the 200R4, They can be built to withstand more abuse than your Dana 36 can!!!!! Good Luck!!!!!!!! Paul

 

[Robin7TFour]

BRIAN, I have plenty of time. tranny is working fine now. i am looking at future mods or changes. i'd rather ask now and start preparing for what i want later.
the motor has a moderate lift cam,roller rocker arms, headers ,edelbrock performer intake,holley 600cfm carb, gm hei ignition. i will eventually check the lift on the cam and degree the lobe separation. and if i get real industrious determine the compression ratio. i can say the cam is fairly healthy ,but that's using the S.W.A.G. method. lopes really good at idle and goes like stink towards the top of the rev range.....
anyway, doing lots of thinking about the car's future....


ROBIN ...the boy wonder???

 

[GerryLP]

Dawg,

I didn't know you had made the tranny swap. Wow! I bet must be nice cruising at almost idle...:L

Was the cross member the only thing requiring modification? How hard was to set the TV cable?