Which Torque Converter?

[PFenstermaker]

Hey guys, next step..
I have a '75 C10 with a basically stock 350.

From my understanding, I can do a torque converter for either a TH350 or TH400 to pair with my TH350, depending on which flywheel I have. How to figure that out? Any other issues or reasons not to go with the TH400 one? Seems like a no brainer to go with the heavuer duty option..

Thanks
- Paul

 

[Honky Kong jr]

You need to find out which flex plate you have 153 or 168 some 168 have mounting points for either. If you have 6 holes with 3 out further then the other 3 its dual pattern, but flex plates aren't rediculously priced for a Chevy and it's cheap insurance knowing it's new.

 

[HotRodPC]

It is a brainer to which one to get. The 1 and ONLY thing better about a Th400 over a Th350 is STRENGTH. Past that, the Th350 IMO is a better transmission if you don't need the added strength. The Th350 has a hair better first gear, lighter weight, less parasitic hp loss to the wheels AND... it's also more tuneable to your liking in shift points and shift firmness via the adjustment of the detent cable and how soon or late you want passing gear to kick in where as the Th400 is only tuneable by the screw in the adjustable vac modulator and passing gear is at wide open throttle only via a gas pedal switch when you go to the floor with and an electric solenoid that is either off or on.

Soooo, now the transmission is explained. Yes, either Th350 or Th400 will work on the transmission. However, the Th400 being a bigger stronger converter, and more designed for bigger heavier vehicles, it's also going to be more mass to spin and not as responsive on the take off. If it were me, I'd run the Th350 converter with the Th350 transmission. There are a few different models though. The stronger of the Th350 converters is the one with the flat pads where you use a bolt and nut to mount to the flywheel, not the ones where the bolt lugs are welded to the converter. I'll look to see if I have a pic to show the difference and probably can even get the model #.

 

[HotRodPC]

Here is a pic of the one I installed in my K1500 when I built the Th350 to replace the 700r4.

 

[Honky Kong jr]

I agree to a point Transgo 400 1-2 kit is awesome and a momentary switch on the shifter for kick down is what I usually do. The 1-2 kit gives you automatic and manual shifting options. Granted they make the same kit for the 350 as well.

 

[74 Shortbed]

The Transgo kit is a "reprogramming" kit, it eliminates the factory safety feature, it will stay in any gear you put it in regardless or rpm, also lets you downshift at any rpm or speed. Only difference between the -1 and -2 is the -2 has larger 1-2 and 2-3 feed holes in the separator plate, so if you don't care about the reprogramming and just want harder shifts all you need to do is drill out the feed holes in the plate and save $45.. Just a little info for those that don't know..

 

[HotRodPC]

I agree to a point Transgo 400 1-2 kit is awesome and a momentary switch on the shifter for kick down is what I usually do. The 1-2 kit gives you automatic and manual shifting options. Granted they make the same kit for the 350 as well.

And you still have all 3 of the negatives. First Gear Ratio, Weight, Parasitic HP loss to the rear wheels. No shift kit will fix that. As said, 400 is for nothing more than needed brute strength. If you don't need it, then go with the Th350. JMO

 

[Honky Kong jr]

And you still have all 3 of the negatives. First Gear Ratio, Weight, Parasitic HP loss to the rear wheels. No shift kit will fix that. As said, 400 is for nothing more than needed brute strength. If you don't need it, then go with the Th350. JMO

I agree my th400 worked well in the Chevelle with how I have it set up. Hopefully I will be just as pleased in its currant home.

 

[Honky Kong jr]

The Transgo kit is a "reprogramming" kit, it eliminates the factory safety feature, it will stay in any gear you put it in regardless or rpm, also lets you downshift at any rpm or speed. Only difference between the -1 and -2 is the -2 has larger 1-2 and 2-3 feed holes in the separator plate, so if you don't care about the reprogramming and just want harder shifts all you need to do is drill out the feed holes in the plate and save $45.. Just a little info for those that don't know..

It will shift automatically if it put in drive pull into 1st and its play time. I have a star shifter with this trans they compliment each other well.

 

[74 Shortbed]

It will shift automatically if it put in drive pull into 1st and its play time. I have a star shifter with this trans they compliment each other well.

Yep, that's what the "reprogramming" does, you could pull it down into 1st at 100mph if you wanted, lol.. I like the Winters shifter myself..

 

[HotRodPC]

I agree my th400 worked well in the Chevelle with how I have it set up. Hopefully I will be just as pleased in its currant home.

No doubt in the right vehicle with the right amount of Torque, notice I said Torque and not horsepower... there is a need for a Th400. Just that most our trucks with mild small blocks don't justify a Th400 unless there is some heavy duty towing going on.

It will shift automatically if it put in drive pull into 1st and its play time. I have a star shifter with this trans they compliment each other well.

I ran a well built by me Th350 with a Quicksilver Ratchet shifter in my 64 GMC 3/4 ton truck. It ran 12.80's in it's best days. Sure I could have justified the Th400 in that truck with that much power, but that was my edge over the guys to spank that ass. I had to rebuild it once a year on avg cuz I'd break it occasionally horsing around and getting a bit to aggresive with it, but hey, when you can build them yourself and a freshen up kit was only $65, it didn't matter much. Most street racers were running 400's. Harder to find, and the 3 disadvantages, I just always had Th350's laying around like paper towels so I always had a back up transmission built and ready to install with the same set up I had in the truck. A swap usually took me just over an hour, 1 out, 1 in and rolling again. Didn't even need to jack up the truck, and didn't even use a jack to get the broke unit out and the rebuilt unit in. Wonder why I have a bad back???

 

[Honky Kong jr]

Yep, that's what the "reprogramming" does, you could pull it down into 1st at 100mph if you wanted, lol.. I like the Winters shifter myself..

The star works like a normal prnd21 until its in 1st and lift the t and pull it back then it's a forward ratchet with a positive stop at 3rd.

 

[Honky Kong jr]

No doubt in the right vehicle with the right amount of Torque, notice I said Torque and not horsepower... there is a need for a Th400. Just that most our trucks with mild small blocks don't justify a Th400 unless there is some heavy duty towing going on.


I ran a well built by me Th350 with a Quicksilver Ratchet shifter in my 64 GMC 3/4 ton truck. It ran 12.80's in it's best days. Sure I could have justified the Th400 in that truck with that much power, but that was my edge over the guys to spank that ass. I had to rebuild it once a year on avg cuz I'd break it occasionally horsing around and getting a bit to aggresive with it, but hey, when you can build them yourself and a freshen up kit was only $65, it didn't matter much. Most street racers were running 400's. Harder to find, and the 3 disadvantages, I just always had Th350's laying around like paper towels so I always had a back up transmission built and ready to install with the same set up I had in the truck. A swap usually took me just over an hour, 1 out, 1 in and rolling again. Didn't even need to jack up the truck, and didn't even use a jack to get the broke unit out and the rebuilt unit in. Wonder why I have a bad back???

I hear ya man. I Ran a 350 in my v8 S10 most were stick or a glide and lately th400. I almost did build a glide for ole Willy lee but I had the 400 left over and it's fresh so in it went.

 

[74 Shortbed]

The star works like a normal prnd21 until its in 1st and lift the t and pull it back then it's a forward ratchet with a positive stop at 3rd.

Never used that one sounds different, I have the Pro-Matic in my Nova and it's a ratchet from neutral to 1st and back to neutral, works pretty good..

 

[Honky Kong jr]

Never used that one sounds different, I have the Pro-Matic in my Nova and it's a ratchet from neutral to 1st and back to neutral, works pretty good..

It's a low gradeish B&M but for what I'm gonna use it for it works. No need for down shifting running threw a mud pit. Lol