MARKUS_P

Just wonder how "bad" the old 350 is compared to the newer transmissions.
Speaking of TH400, TH700R (is this right? :rolleyes:)
As you can see my transmission knowledge is at a minimum, so please help me a bit to change this fact :D
What about efficiency?
What´s the best automatic for our C3´s?
What´s a powerglide?
gear ratios?
Thanks for your input, Markus

mountainmotor

The Turbo 400 is the toughest 3 speed GM auto transmission and a Powerglide is a two speed automatic used in a bunch of low performance GM cars

Here are the ratio's and no I did not type them!

Borg-Warner T-5 (GM Applications) 2.95 1.94 1.34 1.00 0.63
Borg-Warner T-5 (GM Close Ratio) 2.75 1.94 1.34 1.00 0.74
Borg-Warner T-10 2nd Design 2.64 1.61 1.23 1.00 n/a
Borg-Warner T-10 2nd Design 2.88 1.74 1.33 1.00 n/a
Borg-Warner T-10 2nd Design 3.44 2.28 1.46 1.00 n/a
GM Muncie (M-21, M-22) 2.20 1.64 1.28 1.00 n/a
GM Muncie (M-20) 2.52 1.88 1.46 1.00 n/a
GM Powerglide 1.76 1.00 n/a n/a n/a
GM Turbo Hydra-Matic 350 2.52 1.52 1.00 n/a n/a
GM Turbo Hydra-Matic 400 2.48 1.48 1.00 n/a n/a
GM Turbo Hydra-Matic 200-R4 2.74 1.57 1.00 0.67 n/a
GM Turbo Hydra-Matic 700-R4 3.06 1.62 1.00 0.70 n/a


[Modified by mountainmotor, 1:16 AM 1/23/2002]

Larry B.

Most older transmissions lke the TH350,400 are 1:1 final drive These are not overdrive transmissions and are pretty good. TH700 R4 is an O.D. trans with a .7:1 final drive. They are not as tough as the TH400 and are much more expensive to have fixed. The reason people like them(I personally do not) is the economy on the highway along with a low first gear. Stick with a TH400. IMO :spam

norvalwilhelm

The 400 is a stronger transmission then a 350 but it soaks up an extra 35 horse to run. Most cars can get by with the 350 and the extra freed up 35 horse. Hot rod magazine did an article on this. They came up with the 35 horse not me.

MARKUS_P

Thanks for the info.
After reading all this I have to say that my TH350 isn´t the worst choice...
I was told that the gear ratios of some 4 speed are not as close as my 3 speed, thanks for the list, mountainmotor.
Which transmission has the best efficiency? Where is the loss of horsepower at a minimum?

45ACP

"What´s a powerglide?"

There were two different transmissions put in Corvettes known as "Powerglides".

The first, made from '50 to '62, is known by most as the "Cast Iron" Powerglide. I believe it was used in Corvettes from '53 to '61.

The second is the "Aluminum" Powerglide, which was made from '62 to (I think) '73. I believe it was introduced to the Corvette in '62 (along with the 327 CID small block) and replaced by the THM350 in '68.

Both are two speed automatics.

Larry B.

You forgot to say that the Powerglide is a two speed trans.Olds and pontiac had some four speed non overdrive transmissions that had very low first gears. They were cast iron and very heavy too. :jester

Matter

I can attest from personal experience that you will notice the difference in power between a TH400 and TH350. I let someone talk me into a 400 when I was younger because it was tougher. It was... and slower. :)

The 700r4 will be the choice for economy and better low end performance. It's also more expensive to deal with. Your budget will decide.