if the T50 still works the guys with the Chev Monza, Buick Skylark and Olds Starfire who want to keep the car original may want the T50
Stock gear ratios
- Thread starter DoubleV
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if the T50 still works the guys with the Chev Monza, Buick Skylark and Olds Starfire who want to keep the car original may want the T50
I had the T50 in my 1978 442 I just sold back in April of this year. The only rear end gears available were the 2.56s with the Olds 260 V8 motor. You could get the T50 behind the Buick 231 V6 and that got you 2.93s. Again, the only available gear. I believe it was the same in 1979 also. I Back in 2003 when I got the 442 I wrote to the GM Heritage Center and they sent me a huge packet of info on the car and all its specs, including the transmission gears.
1st gear - 3.10
2nd - 1.89
3rd - 1.27
4th - 1.00
5th - .80
Reverse - 3.06
The Saginaw 4-speed had no lines on the input shaft so it had 2.85, 1.91, 1.31?, 1.00 gearing for cars with the Chevy 305 V8 2 barrel. The only available option in 1978 was a 2.73 rear. That changed in 1979. The 4-speed was available with the Chevy 305 4 barrel and a 3.08 rear.
Didn't want to sell the 442 but I couldn't keep 4 Oldsmobiles. The guy I sold it to lives in the next town. Maybe...
1st gear - 3.10
2nd - 1.89
3rd - 1.27
4th - 1.00
5th - .80
Reverse - 3.06
The Saginaw 4-speed had no lines on the input shaft so it had 2.85, 1.91, 1.31?, 1.00 gearing for cars with the Chevy 305 V8 2 barrel. The only available option in 1978 was a 2.73 rear. That changed in 1979. The 4-speed was available with the Chevy 305 4 barrel and a 3.08 rear.
Didn't want to sell the 442 but I couldn't keep 4 Oldsmobiles. The guy I sold it to lives in the next town. Maybe...
Good info thanks. I'm definitely keeping the T50 whether I run it or not in the future.
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Interesting it has the better .80 od gear. What size are the stock tires? With a 205/70R14 it run at 1650 rpm at 60 mph. With 3.23 gears it would run at 2000 rpm at 60 mph, still decent.
I always found it interesting that Oldsmobile used a 2.56 rear in the Cutlasses with the T50 since 5th gear was overdrive. Made no sense at all. The 2.56s were good highway gears for economy already without adding an overdrive. 5th gear gives you an overall ratio of 2.05 (2.56 * 0.8). Maybe that's why the car was rated 20 mpg city and 29 mpg highway for 1978. Impressive for the day. They should have given the car 3.08s or even 3.23s.
You'll find alot of non performance factory G bodies with a 4 speed overdrive with a 2.41 rear. My GP came with that gearing
Because tire technology of the day couldn't cope with the 260's massive torque when coupled with any bigger gearing!
Seriously I'd say it was cuz the 260 option was meant for pure fuel economy and it was probably more efficient when run at a very low rpm. That and GM were a bunch of bean counting idiots.
Also, first gear in the T50 is steeper than other available transmission's. Engine would rev up too quickly in 1st if you had steep rear gears.
Those are my guesses at least but yeah I think they coulda went a bit steeper with the gearing regardless. One day I will change gearing and see how it goes.
Seriously I'd say it was cuz the 260 option was meant for pure fuel economy and it was probably more efficient when run at a very low rpm. That and GM were a bunch of bean counting idiots.
Also, first gear in the T50 is steeper than other available transmission's. Engine would rev up too quickly in 1st if you had steep rear gears.
Those are my guesses at least but yeah I think they coulda went a bit steeper with the gearing regardless. One day I will change gearing and see how it goes.
I can't say I've ever seen or heard of any '79 Olds with a 305 4v, 4spd and 3.08 rear.. that would likely be ultra rare...
Tom
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