Automatic transmission upgrade

[Cheyenne1010]

I have a 1973 C10 long bed,350 motor with a 350 turbo transmission.so when I'm driving my truck and it feels like it needs another gear change after it's gone through the 3 gears.i dont have a tac guage on my truck but i can hear the rpm's a little high and i just dont like the way it sounds.i feel it would be better if there were 4 gears.So my question is what is an upgrade for my truck as far as the transmission goes?im on a budget so throwing in a newer trans that will cause additional electrical work done to my truck to operate the newer trans is something i want to avoid.i know alot of people that have c10 pickup's and it seems like their all trying to make their old truck in to a new truck and there's nothing wrong with that,i just like my truck the way it is except for the transmission.
     
       Thank you for your time guy's

[VileZambonie]

700R4 would be the best option

[Cheyenne1010]

Does the 700R4 have any electric plugs that need's voltage for it to operate?

[MrFiveOh]

Does the 700R4 have any electric plugs that need's voltage for it to operate?

it does require a 12v source, that can be wired to the fuse box. if your adamant on non electric manual, geardrive or 350c is your only other options

[VileZambonie]

TH350C and 700R4 uses a 12 volt solenoid operated torque converter. Just note that having a lock up converter does not make it electronic. It can be wired up very easily and inexpensively. There are plenty of options for 700R4 lock up kits

[Stewart G Griffin]

First, what is your rear axle ratio?


Also, having a lockup converter might only bring the rpm down a few hundred---100 to 300rpm maybe?  If at all.   i switched from 350C to regular 350 and notice no rpm change at cruise.  B+M traveler converter, which i assume is a relatively tight converter?

[Cheyenne1010]

I'd have to check on the gearing ratio on rear end,i'll be back with that info

[Henry]

Hi Cheyenne1010:
Assuming your drivetrain is all original from factory, it sounds as if you have a rear end ratio that is optimized for towing or hauling with your TH350. As others have said, the first thing is to establish what your rear end ratio is right now. If your truck is simply a grocery getter and daily driver to work, you could possibly simply change out your rear end ratio to get your engine to slow down at highway speeds. Be aware that this may not allow your engine to be at optimal rpms for towing or hauling big loads...but maybe you dont care about this. I think the rear end gear change out may be the simplest change. As VZ has said, the 700R4 may be a solution as you get 4 gears now, but you still need to compare what the ratios are in this trans with your TH350 and what you have in the rear. Be aware that the addition of a wire may not be your biggest mod: I think the driveshaft between the TH350 and the 700R4 are different just like the driveshaft between the TH350 and TH400(700R3) are different. If you let us know what your rear end ratio is, rear tire diameter, we can probably help you figure out what your options are.
Regards,
Henry

[MrFiveOh]

Hi Cheyenne1010:
Assuming your drivetrain is all original from factory, it sounds as if you have a rear end ratio that is optimized for towing or hauling with your TH350. As others have said, the first thing is to establish what your rear end ratio is right now. If your truck is simply a grocery getter and daily driver to work, you could possibly simply change out your rear end ratio to get your engine to slow down at highway speeds. Be aware that this may not allow your engine to be at optimal rpms for towing or hauling big loads...but maybe you dont care about this. I think the rear end gear change out may be the simplest change. As VZ has said, the 700R4 may be a solution as you get 4 gears now, but you still need to compare what the ratios are in this trans with your TH350 and what you have in the rear. Be aware that the addition of a wire may not be your biggest mod: I think the driveshaft between the TH350 and the 700R4 are different just like the driveshaft between the TH350 and TH400(700R3) are different. If you let us know what your rear end ratio is, rear tire diameter, we can probably help you figure out what your options are.
Regards,
Henry

In regards to the driveshaft length, if its a short bed and the th350 has the 9inch tailshaft, the same driveshaft can be used with a 700r4, you just have to slide the transmount back a couple inches and drill new holes to mount. Thats what i did on my 74 SWB.

Id would check the rear gear ratio and overall tire diameter as well. those play a role into overall gearing. id use grimmjeeper dot com as a reference comparison.