Thoughts on Transmission Choice

[Slim57]

Going to try my hand at this...

Am at a cross roads as such in regards to powertrain version to go with in our '57. Guiding post is an homage to 1960's hot rod with some twist. Plan is a reasonable budget build to "clean" driver quality for weekends and fun runs. Looking to center around the rear end I have available- Currie Ford 9" with finned aluminum center section - Truck Arm rear suspension.

10989

With this in mind, here goes my dilemma was hoping for thoughts on. Pondering two directions: one is old school SBC (350 CI) with 3 speed TH transmission, other is something along the lines of LQ9 (6.0L) and 4L80. May be some insight to thoughts below could help me "out of the woods".

Have in the garage a freshly rebuilt TH400. Although rebuild was in early 90's and has not been installed in vehicle since. According to dad, it was a "performance rebuild" (street/strip based) with manual valve body. No torque converter at this time.


So... am thinking to swap valve body to allow for auto shift pattern. Question is, since trans has sit for so long (~30 years) would there be an issue using without first inspection/freshing of internals? Guess this leads me to my overall choice. If cost of work on transmission comes to a point maybe new unit is more cost effective??? Then would that justify moving to newer four speed transmission and therefore more modern LS based platform? Any thoughts are constructive opinions would be greatly appreciated. Thanks for reading!!!

[Chevy Chase]

Back in the 80's I installed a Dana 60 Ford truck rear end in a '55 Chevy station wagon. The rear end was ~ 4" wider than the 55 Chevy rear end. I radius'd the rear quarter panels and slightly flared the quarter panels. BTW the truck rear end was a six lug with large wheel studs. Looks like your Currie Ford rear end has large six lug studs too.

[BamaNomad]

what is the gear ratio in the rear? What size tires do you envision it running? Do you anticipate any 'longer' highway trips? Or just local? I'd answer all those questions before I decided if I were you.

PS. The TH400 is a HD transmission, capable of standing up to 400+ hp, but it also have more parasitic loss than say a TH350 (or 200R4)..

[Slim57]

Back in the day help dad put a Dana 60 underneath his 48 Willys 4X4 Wagon. He got tired of breaking the Dana 44 that came with it. Upside to reared is it 59" across. Downside is it has 5 on 5 1/2 bolt pattern. Planning on running steel wheels with center cap so maybe won't matter much???

To Bama's point- only have Strange Mfg carrier (third member???). No gears. Had envisioned 245/5/17's rear and 225/17/50 front. (somewhere had right done after see a few cars I liked, argh). Travel wise mostly in town and from time to time places we can reach within day roundtrip. Although would be nice to head back east to the Nationals some day???

Had thought it would be neat to get either and 18" Airstream or equivalent Shasta travel trailer some day. Wife has not really warmed to idea, so maybe not.

[BamaNomad]

So you want to use the rear you have because you have it and it will be strong? Probably much stronger than you really need for your '57 Chevy. Your rear is 59" from wheel to wheel? 59" would be good I think if that's what it is. The stock original rear is between 59 and 60" from lugs to lugs (where the wheel bolts on - not just the housing). I'm guessing that Dana60 gears will be lots more expensive than more common Ford or Chevy gears...?

[enigma57]

The question of small block or LS engine is one you will need to decide, Slim. Each has their strong points and their weak points. As you have this TH-400 transmission and Dana 60 based rearend needing internals...... Why not consider a 502 big block in mild state of tune (500 HP) and gear the car accordingly? With that much torque in a not very heavy car, you wouldn't need to be concerned with high stall converters or overdrive transmissions.

Just put 3.00 rear gearing in and a near stock 2,000 stall converter and you will have all the performance you need in a road car.

As long as your TH-400 transmission has been in dry storage since rebuilt, just get a new seal for your new converter and go. No need to tear it down beyond changing out the valve body if you need to. Is it a full manual valve body or one that will either shift automatically or remain in 1st or 2nd gear when you get down on it until you either shift up manually or let off the gas and it will then shift up automatically? Reason I ask is that I special ordered a new '69 Nova SS with a TH-400 set up that way behind the L78 375 HP 396 and it was a great transmission for high performance road use. Now of days, there might even be a lock up converter for the TH-400. Worth looking into, anyway.

All the best with your build,

Harry

[markm]

So you want to use the rear you have because you have it and it will be strong? Probably much stronger than you really need for your '57 Chevy. Your rear is 59" from wheel to wheel? 59" would be good I think if that's what it is. The stock original rear is between 59 and 60" from lugs to lugs (where the wheel bolts on - not just the housing). I'm guessing that Dana60 gears will be lots more expensive than more common Ford or Chevy gears...?

I started with a 62 inch wide 1/2 ton Ford 3.54 Dana 60 Powerlock , narrowed it to 56 and had less than $500 when done and stronger than a 9 inch Henry ever built. As far as TH400s go they take fewer mods to go racing than any other trans.

[56ls408]

Going to try my hand at this...

Am at a cross roads as such in regards to powertrain version to go with in our '57. Guiding post is an homage to 1960's hot rod with some twist. Plan is a reasonable budget build to "clean" driver quality for weekends and fun runs. Looking to center around the rear end I have available- Currie Ford 9" with finned aluminum center section - Truck Arm rear suspension.

10989

With this in mind, here goes my dilemma was hoping for thoughts on. Pondering two directions: one is old school SBC (350 CI) with 3 speed TH transmission, other is something along the lines of LQ9 (6.0L) and 4L80. May be some insight to thoughts below could help me "out of the woods".

Have in the garage a freshly rebuilt TH400. Although rebuild was in early 90's and has not been installed in vehicle since. According to dad, it was a "performance rebuild" (street/strip based) with manual valve body. No torque converter at this time.


So... am thinking to swap valve body to allow for auto shift pattern. Question is, since trans has sit for so long (~30 years) would there be an issue using without first inspection/freshing of internals? Guess this leads me to my overall choice. If cost of work on transmission comes to a point maybe new unit is more cost effective??? Then would that justify moving to newer four speed transmission and therefore more modern LS based platform? Any thoughts are constructive opinions would be greatly appreciated. Thanks for reading!!!
the internal clutch piston seals will get hard as a rock after sitting long periods maybe yours haven't since it hasn't been heat cycled but i wouldn't put it in without at least pulling the front pump & checking the seals in forward & direct not hard to do if they are still pliable then the ones in intermediate will be the same