Stock TQ or aftermarket

[Canadian1968]

I am going to have my transmission rebuilt over the winter . I am wondering if I should get a new TQ or just stick with the stock as lon as it's alright ?  The car is mild  446 with comp cams 274xe cam. 906 heades cleaned up and gasket matched , headers and 2.5 x pipe exhaust . Stock 3.23 gears and running a 26" tire . Would an aftermarket converter make much difference ?

[Nacho-RT74]

when I read TQ thought on carburetor... you meant TC.

[Canadian1968]

yes sorry my mistake ! talking about Torque converters ! which help transFer the TQ

[firefighter3931]

That engine combination would certainly benefit from a higher stall speed. 

Something in the 2600-2800 rpm range would be ideal. PTC or Turbo Action 11in TQ converter would be my choice. 


Ron

[John_Kunkel]

Depending on which stock converter you have, an aftermarket might not be much of an improvement. The factory high-stall converter is highly under-rated.

[justcruisin]

I would say it depends on the converter you are running now, I had a similar combo running 3.23's with a 12" converter, swapped it out for a 11" and the power off the line was greatly improved - flashed to 3200 rpm where the 12" would go to 2200, but I will say that while the car drove fine on normal driving the car felt a little slugish on moderate acceleration. Overall - worth it IMO, If you have a 12 and go to an 11 make sure you go with a quality unit.

[Canadian1968]

I understand the stall speed but what is difference with the 10/11/12 "  As far as I know it is the factory converter in there right now. It's an orginal 68 R/T car. Is there a way to tell which converter I have without pulling it ?

[justcruisin]

If you pull the tin plate off on the bottom of the trans that faces the engine you will see the torque converter, the 12" ( 11.75") will have 1/2" between the edge of the ring gear teeth to the torque converter case and the 11" (10.75") will have about 1". To my knowledge, the factory never installed a 10" converter. Most probably you will find a 12" converter.
If you do change it, use a converter with the larger bolt pads.

[Canadian1968]

ok well it is 12" then because I just had it off the other night and there is not much space at the sides at all !  But what us the difference between the sizes ?

[justcruisin]

A lot depends on how they are built but basically the smaller converters have less driving area so the engine needs to spin them faster to achieve full drive. As a general rule, usually, given the same load, a smaller converter will stall higher than a larger one, but regardless they need to be built right and be suitable for the application. Smaller converters can put a lot of heat into the trans fluid in a street situation, especially with tall gears such as 3.23's. A stand alone cooler is a good idea.

[BSB67]

Would an aftermarket converter make much difference ?

What would be a meaningful difference to you?

What would you be hoping for in the cars performance and characteristics in changing the converter?

[Nacho-RT74]

Depending on which stock converter you have, an aftermarket might not be much of an improvement. The factory high-stall converter is highly under-rated.

I was to say that... per what I have read some SB got high stall TCs on the rate Ron posted... diff stuff is how efficient they are against the PTC or any other aftermarket piece.

Then... how much worths that benefit ? spend $300-500 on a TC that you won't really need ? on a small improvement piece for a Street car ?

Maybe worths more spend that on a Strip car!

some to think about

just an opinion, not saying you need this or that

[Canadian1968]

well that's why i was asking the question . Would it really be worth it in my situation. The car is way more a street car than a track car. But I built a motor and would like to make sure it's working the best it can. 

What am i looking for? Well hey let's face it I belive a lot of us drive our cars for the fun factor. So if my current setup was taking away from some of my engines "grunt " then i would like to way the options is it worth it.  Currently the car is fun to drive , but out of the hole it seems like a bit of dog. I can't quite figure out if it's just cause I am spinning the tires or is it something else ... aka maybe the tranny slipping a bit ?  I stomp n it from 40mph and sometimes it puts me in my seat and pulls like scared cat , other times it just doesn't seem to have it .  I break the tires from 10 -15 mph roll .... other times meh again just not there .  Hole shots light them up but there just isn't the pull .   I know the car isn't an 11 sec car and I am not gonna lift the wheels but I know it's not a Honda civic either !

[firefighter3931]

Would it really be worth it in my situation.

Yes it would be worth it 

Here's why : That cam doesn't really come on until 2500-2600 rpm. A low stall like the factory 12in unit will usually go 1800-2000 behind most 440's. So the idea is to pick a converter that matches your engine's powerband. The better it's matched....the more fun the car will be to drive. 


The sluggish off idle performance is directly related to the less than ideal stall speed in this particular case 



Ron

[Nacho-RT74]

I'm not saying a matched TC won't be worthly, but HOW MUCH for it ?... meaning you can get a good high stall stock unit that could be enough, or an aftermarket HiPo unit what is definitelly more efficient, where price difference can be more than double without need for it for the useage.

Just saying... once again I'm not meaning I'm right or wrong, since I'm an unexperienced newbie on this.

But of course get the right TC converter stall ratio will be worthly and noticeable.

I rememeber have read in several threads about that on board where were posted the FSM tables about stock TCs specs.... some being rated on 2600-2800 stall ratio ( of course behind an specific engine combo )... Those maybe could be on $100-150 price rate around, against maybe same stall ratio for an aftermarket HiPo unit rated on $300-400 price. Of course these are more efficient.

Sorry, I tipically think on the cheap LOL. If I had the money wouldn't think on that.

Myself... 451 with 440 crank and 400 rods, around 10.2 CR, Ported heads big valves, 282HDP Crower cam, 3.55 SG on 27" tires. Running a 175K MP TC, which is not for sure the most efficient cam, but I'm not a racer. Just paid $75 for the TC rebuilt unit on its Chrysler MP box. I think by now is good enough. May I get better performance paying $300 for an aftermarket Unit... SURE... Do I need it ?... not by now, neither can pay more at this moment. By catalog specs, it stalls on 2400-2600 rate behind a 440 ( which is what it is a 451 on a lower deck block ). I think for now is good enough

[Nacho-RT74]

I followed this table... by the cam specs and the engine crossover on table, I could be using even the 166K unit ( which I also have around but with counterweights welded because was behind the cast crank my 400 had ), but went higher to supposelly get better performance.

As I told... I spent $75 on the TC ( maybe was $100, can't recall ) and per the table I'm somehow matched.

The deal is, MP is not offering these anymore as far I know from new the shelf, but maybe some dealer still get rebuilt units or you can find some used around.

Some factory units are as far I know in fact same MP units.

Was maybe better get a TCI or some other unit with similar specs being more efficient? yes sure... Do I really need it for the useage? I don't think so, but maybe a later upgrade. $75-100 against $300-400... I can wait for that untill get a better economical situation. For a while I'm having some fun driving my car around ( well, I'm missing my car right now LOL )

[Canadian1968]

Yes the price is a factor for me. A quick look has showe me prices in the  $600 + range. This not what I was looking to spend on top of the tranny itself this  winter. 

I am in Ontario Canada,  anyone in this area have suggestions on where to look for torque converter

[firefighter3931]

One of our members installed a Hughes tq converter in his car awhile back and it really woke the car up. Mild street build similar to yours.

This is a descent "budget" converter that won't break the bank 

https://www.summitracing.com/int/parts/hup-24-25/applications


Ron

[Canadian1968]

question .... does an aftermarket come with the ring gear to engage with the starter or do u have remove from stock and pUT on the new one ?  And 10 or 11" with that bolt to my exsiting flex plate ?

[justcruisin]

Yes it will come with the ring gear and you will need a new flex plate.

[Canadian1968]

geez dont like this converter shopping stuff ! Some parts they give you more info than others !

this says small bolt circle ?  so would it match to the 10" hughes converter
https://www.summitracing.com/parts/dcc-4529751

[justcruisin]

If you are looking at the converter that Ron suggested that is an 11" converter. The flex plate you have linked to is a good choice and will have the same bolt circle as that converter - 10" bolt circle. I am unsure if that converter comes with 7/16 bolt pads which you will need to run that flex plate, it would pay to check, it doesn't say so they could be 5/16". Also - if your engine is 70/71 hp and running the 6 pack rods you will need the correct balanced flex plate, that one wont work.

[Canadian1968]

The block is 68 with LY rods 

[BSB67]

Every time you drop the hammer at 40 mph, the result should be the same.  Same with 10 - 15 mph.  So the difference is either a slight difference in speed allowing the tranny to drop to 1st verses 2 (at 40 ish), or the road conditions (breaking loose at 15) and/or weather conditions.  People put a lot of value and emphasis on what happens on the street when you drop the hammer from a roll.

Actual quarter mile times will not really change in any meaningful way without a change in tire to improve traction.

With all that said, there will be a sweet spot from a roll when driving on the street where the car will fell snappier and the tire will spin easier. 

[c00nhunterjoe]

What pistons went in it? You probably wont need alot of converter. Is 2 or 300 rpm really worth the change?  If it dead hooks at the track, going from a stock 12" to the 11" flashing at 22-2500 will only gain .2 seconds max on that combination.

If you want a light to light nasty car with a mild motor, then stick a loose converter in it with a set of 4.11s. If this is a highway speed cruiser, then leave it alone.