Overdrive transmission

[Kern Dog]

Top gear -

50-60 years ago the cruising speed on the highway wasn't as high on average.  There were 80 mph rural places but it wasn't common in the urban areas like now.   

Throw in the fact that the original owner usually ditched the car by 50-70,000 miles, and resale wasn't even a thing . . . they just didn't care about engine wear.  They didn't even give the engines moly piston rings.  And they certainly didn't care about gas mileage. 


Deeper axle gears & lower 1st gears -
 
Muscle cars were medium-heavy bodies + 400+ pounds of torque + 14x5 rims and bias-ply tires.  Low 1st gear ratios would have been pointless.  Not enough traction to use it. 

The 1st gear ratios were getting lower in the 1980s-90s when sporty OEM cars were up to 7-8" wide rims and radial tires. 

That is one way to look at it but it is a chicken and egg thing.

Did people trade out cars at 70,000 because they were worn out? If so, wouldn't adding an overdrive back then extend the life of the cars, increasing their value and likelihood that the owners would trade them in a couple years later?

Seriously...They already knew the merits of overdrive in manual transmissions, adding it to an automatic could have happened before the 80s. The Torqueflites came out in the early 60s, cars got faster and heavier through the late 60s/early 70s. Fuel economy did matter to buyers, not so much the Feds.

Even consider that the automatic overdrives spread in the 80s to 4 speeds. It took American automakers quite awhile to get them to a 5 speed. In the early 2000s, there were 5 and 6 speed autos. The last few years it seems to have peaked at 10 speeds.
My point is that it seemed like the automakers were lazy to implement this feature back when our beloved classic Chargers were new. Back then, you had a wider assortment of engines than today. For example, a 1970 Charger could have been fitted with a 225 slant six, a 318, a 383 2 barrel, a 383 4 barrel, a 426 Hemi, a 440 4 barrel or a 440 Six Pack. Yes...seven engine choices. The Chargers of today have 4 choices. A V6, then the 5.7, 6.4 and the Hellcat 6.2.

[Mike DC]

Oh yeah, the short trade-in lifespans of muscle cars was an engineered thing.  Planned obsolescence. 

American cars got better in the 1980s-90s because people had gotten a taste of something else.  The public abruptly switched to a lot of foreign cars in the later 1970s/early 80s because gas prices shot up.  Those imports were smaller/slower vehicles with better mileage.  But they also lasted longer.  That finally put the pressure on Detroit to make cars that get better mileage and last longer too.   

[hudak69rt]

I like to open it up on the back roads, and cruise at 80 on the freeway, but the vast majority of my driving is in town, and I'm not gonna act stupid there. 
No track time at all. I just like to pull onto the freeway quickly and maybe stop to stop when it's quiet. I currently have 3.23 gears and they're alright, but an overdrive would be nice. I'm doing the same to my Gran Torino. Going from 2.75 with the stock 3 speed auto to 3.70 or thereabouts with an overdrive. 28" tall tires on both cars.

check out my build I have a 200r4 stage 3 built pretty much bolt except hacking up crossmember mount!

[Dino]

I like to open it up on the back roads, and cruise at 80 on the freeway, but the vast majority of my driving is in town, and I'm not gonna act stupid there. 
No track time at all. I just like to pull onto the freeway quickly and maybe stop to stop when it's quiet. I currently have 3.23 gears and they're alright, but an overdrive would be nice. I'm doing the same to my Gran Torino. Going from 2.75 with the stock 3 speed auto to 3.70 or thereabouts with an overdrive. 28" tall tires on both cars.

check out my build I have a 200r4 stage 3 built pretty much bolt except hacking up crossmember mount!

Nice! If I stick with automatic this may be the best way to go.

[Nacho-RT74]

https://www.passonperformance.com/categories/complete-transmissions/product/502-passon-performance-a-855-five-speed-transmission

 
Dunno what happened with these guys... but if was available (and having solved all their issues and having the funds), that would be my bid.

[hudak69rt]

I like to open it up on the back roads, and cruise at 80 on the freeway, but the vast majority of my driving is in town, and I'm not gonna act stupid there. 
No track time at all. I just like to pull onto the freeway quickly and maybe stop to stop when it's quiet. I currently have 3.23 gears and they're alright, but an overdrive would be nice. I'm doing the same to my Gran Torino. Going from 2.75 with the stock 3 speed auto to 3.70 or thereabouts with an overdrive. 28" tall tires on both cars.

check out my build I have a 200r4 stage 3 built pretty much bolt except hacking up crossmember mount!

Nice! If I stick with automatic this may be the best way to go.

.  Only problem is the dealing with the neutral safety switch my car is completely rigged with the wire to get around but it works for now plan in dealing with it next month but also deeper 1st and 2nd gears over the 727 so better low end and high end. 200r4 also just mechanical not of that electrical like the silver sport set up I had a guy I'm sure he sold in nj brand new stage 2 set up from silver sport for like 4k but torque rating of only 550 to low if that what you plan on making that's why I chose and overbuilt one. Do it right should only have to do it once. They also offer a lifetime freshen up for 450.00