transmission swap help...

[draggin49]

Looking to swap out the 3 on the tree manual transmission and install an automatic tranny operated on the column.

The truck is a 1969 shortbed, has low gearing.what was the lowest factory gearing installed?

Trying to decide if I should install the powerglide out of my 69 camaro and out a taller gear ratio in.

Or should I leave the low gear ratio and install a 700r4 so I have overdrive and the low gears would be manageable.

Im trying to get an idea of how big a difference moneywise im looking at using the powerglide I already have vs going the 700r4 route.

Look forward to your guys input
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[doc74021]

I have a 69 also the original was a straight 6 with 3 in the tree and had 411 gears.I now have a 350 in the truck and I am swapping to a 700r4 depending on what your doing with the truck (dailey driver or not) and how much horsepower you want determines your gear most chevys for gas mileage use a 308 but I have seen drag guys use up in the 500's I am thinking of going with a 373 not sure if it will be high enough
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[draggin49]

I think mine has 4.11 also. This truck im just keeping the stock 350,maybe do intake, carb, heads, cam etc nothing too crazy.

I believe my 49 ford has 4.11 or at least 3.73s
It had a flathead with 3 on the column.swapped in a 302 and overdrive out of a wrecked 5.0 mustang and it runs awesome. Also doesnt turn high rpm on the freeway. Much better for daily driving. I had a chevelle with 4.11s and a powerglide, freeway was a nightmare!!!
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[ScottG]

Originally Posted by draggin49

Looking to swap out the 3 on the tree manual transmission and install an automatic tranny operated on the column.

The truck is a 1969 shortbed, has low gearing.what was the lowest factory gearing installed?

Trying to decide if I should install the powerglide out of my 69 camaro and out a taller gear ratio in.

Or should I leave the low gear ratio and install a 700r4 so I have overdrive and the low gears would be manageable.

Im trying to get an idea of how big a difference moneywise im looking at using the powerglide I already have vs going the 700r4 route.

Look forward to your guys input
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Hey Ojai!! I'm in Ventura. I swapped from a 4 speed to a TH400, with 4.11's. Didn't like it at all. Screamed pretty good on the freeway, so I wnet to a 700r4. Also swapped rear ends> I have 3.54's now. Much better, if you're gonna drive it regularly.

[draggin49]

I 100% agree, better to do the extra effort and make the truck driver friendly and practical so you can hop on the freeway and not have issues
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[scrappy]

Your tire size is also a factor in figuring out gear ratio's. I have 255/60-15's on my 70(about a 26" tall tire) with the factory 3.73 gear's & t350 trans & mine turn's about 3000rpm at 70mph on the freeway. I want to go to 3.55 gear's with an od trans so it ain't screaming at me going down the road. IMO if your not going to drag race your truck don't use the glide.

[draggin49]

Ok, only way I was considering using the glide was to swap the 4.11's or 3.08s
May just go 700r4 so I dont have to mess with the rear end.
Im unsure on if itll have 18's or 20's all the way around.considering air suspension so I dont know how tough to run 20s in the front.I know out back is easier
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[MrBeast]

If you are going to drive it a lot I say go with a 4L60E or 4L80E they are a better, stronger transmission, they are computer controlled and they have a lockup function that helps you get better mileage and you can program your shift points. These transmissions will pay for the difference in cost in the gas you save.

If you go the extra mile and add EFI as well, you will be amazed how much better your truck runs.

Something to consider is you can buy a early 90's suburban in running condition for 1500 bucks, it will have everything you need to do this swap. Often you can even find them with good solid engines in them.

I would much rather go this route than mess around with trying to upgrade to a power glide, as well it will get you the serpentine drive assembly, which will be much nicer than playing with V belts and make getting parts easier too, as well you will get a 105 or 120 amp alternator out of the deal.

[54belair]

The bottom line is engine RPM. If you want fuel mileage, you need low rpm--however or whatever trans. you use.
If you want a "quick" ride, then you go with a higher numerical rear. If you are more interested in hiway cruising then you will need a lower numerical rear.
When you do your calculations using final trans gear ratio, rear end gear, and tire size---you need to shoot for 2200-2400 rpm at hiway speed (whatever cruising speed youd like)

Do a search for figuring final drive ratios, you will find a few sites that have all the formulas you need. (there is a camaro forum and another for firebirds that have the formulas---all you have to do is plug in your numbers

[54belair]

try this one

http://www.csgnetwork.com/multirpmcalc.html