Gears or torque convertor

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Silent Thunder

Silent Thunder

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My mechanic feels I will get more pep or off the line performance by by having the torque converter rebuilt with a higher pounds opposed to going from 3.23 to 3.91 gears in the rear end. The car is a 64 valiant with a 273 auto, 4 barrel carburetor. I've never done either so what are your thoughts? I have a sure grip rear end and right now can't burn rubber down hill!
 
If your engine is a stock 4bbl and it's more of a cruiser and you do any highway driving i would opt for the converter and keep the 3.23's. Your tires are probably fairly short, 25" range i would guess, so that's probably enough gear for now. If you want to build up the engine and race some then you should probably do both.
 
Just cruising down the road but want to be respectable. Sounds like the converter is the way to go then. I also notice that currently the tranny shifts all the gears at low RPM's by 30 I am in 3rd. Of course manually shifting I am able to shift at higher RPM's and it moves better.
 
Silent Thunder said:
Do you need my VIN number? I thought I provided quite a bit in my first post. I don't know anything about crystal, around here we prefer brass. :toothy8:
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I like that...lol.

The 273 even in four barrel form is a low torque engine, best power is usually between 3-5,000 rpm's. I don't want to bad mouth the big mail order houses because for the most part, they are great. But when it comes to torque converters i prefer a good specialty builder and in your case with the low torque application, one of the converter specialists can build you one that has a true 3 thousand'ish stall and still drive like a stock converter around town. As far as the shift rpm, you can manually hold it for what you need, although a floor shift does make it a little easier.
 
I am wondering if the kick-down linkage is functional or needs adjustment. It should hang longer in the gears and kick-down to lower gears by giving it full throttle.
 
My mechanic feels I will get more pep or off the line performance by by having the torque converter rebuilt with a higher pounds opposed to going from 3.23 to 3.91 gears in the rear end.
Click to expand...

Using your first sentence I would say converter as well. It will allow you to "launch" quicker. As far as pulling you probably won't notice a whole bunch of difference.

And it really would help to know more about the engine, stock? cam? headers? etc. It all adds up.
 
Silent Thunder said:
Do you need my VIN number? I thought I provided quite a bit in my first post. I don't know anything about crystal, around here we prefer brass. :toothy8:
Click to expand...

Engine size
Type of intake manifold
Type of exhaust
Compression ratio
Camshaft info
Transmission type
Vehicle weight


You included almost nothing. I wouldn't trust anyones recommendation based on what you provided.
 
OP I'll go with a little more cam with the converter swap
 
Keep in mind if you go with a converter first. Any changes you make later down the road like power or gears will change and effect the converters performance.

DO NOT BUY AN OFF THE SELF CONVERTER LIKE B&M OR anything similar.

I got mine from dynamic converters.
 
You need to know your cam specs before ordering a higher stall convertor. The cam and torque convertor are closely related in terms of performance, believe it or not.

I rebuilt engines for a living for 10 years. I've seen how mismatched parts can make a car a pain to drive. Properly matched parts make the difference between a car that runs good and one that runs GREAT.

My co-worker was building a brand X engine back in the mid 90's. He talked to the B & M guys at a trade show about getting a custom convertor. The main thing they were interested in were the cam specs. That car ran like a raped ape. It would destroy the tires from a 15 mph roll. It was also very docile to drive every day.
 
lilcuda said:
You need to know your cam specs before ordering a higher stall convertor. The cam and torque convertor are closely related in terms of performance, believe it or not.

I rebuilt engines for a living for 10 years. I've seen how mismatched parts can make a car a pain to drive. Properly matched parts make the difference between a car that runs good and one that runs GREAT.

My co-worker was building a brand X engine back in the mid 90's. He talked to the B & M guys at a trade show about getting a custom convertor. The main thing they were interested in were the cam specs. That car ran like a raped ape. It would destroy the tires from a 15 mph roll. It was also very docile to drive every day.
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This cant be stressed enough. You have to utilize the power band when you get a converter. And make sure you have a good tranny fluid cooler too. You can cook a tranny in short order with out one.
 
71swing said:
Keep in mind if you go with a converter first. Any changes you make later down the road like power or gears will change and effect the converters performance.

DO NOT BUY AN OFF THE SELF CONVERTER LIKE B&M OR anything similar.

I got mine from dynamic converters.
Click to expand...

Read this once and read it again. Converters don't need to be overlooked. They're just as important as a cam chose.
 
When I ordered my converter from Frank Lupo, he wanted to know everything about my car, and I mean EVERYTHING!! Tire and rim size, rear gear size, transmission gear ratio's, cam size, carb and intake choice, compression, car weight, my projected useage for the car, even my Mom's maiden name!!

You can't give too much info to a converter builder to build the best unit for your combo, but you also can't expect the unit to substancially increase performance without a complete package. Mismatched or incorrect items in your combo can have as much or more negative effect on your performance as a nice new piece of equipment can add. If you are happy with all of the elements in your combo as is, by all means go for a better converter!! Geof
 
OldmanRick said:
If your engine is a stock 4bbl and it's more of a cruiser and you do any highway driving i would opt for the converter and keep the 3.23's. Your tires are probably fairly short, 25" range i would guess, so that's probably enough gear for now. If you want to build up the engine and race some then you should probably do both.
Click to expand...

OldmanRick said:
I like that...lol.

The 273 even in four barrel form is a low torque engine, best power is usually between 3-5,000 rpm's. I don't want to bad mouth the big mail order houses because for the most part, they are great. But when it comes to torque converters i prefer a good specialty builder and in your case with the low torque application, one of the converter specialists can build you one that has a true 3 thousand'ish stall and still drive like a stock converter around town. As far as the shift rpm, you can manually hold it for what you need, although a floor shift does make it a little easier.
Click to expand...

When i made these posts yesterday i just had the feeling the op's car was close to stock. Hopefully he didn't get scared off and can offer a little more info. on his combo so we all can help him.
 
DJV's car sure seemed to run OK with 3.23's and a tunnel rammed SB... Oh the converter made a world of difference.

Spend the money on a good converter. If it's not a race car, get something that stalls in the 2500 range and flashes HARD to the high 3's, 3700-4000 range. It will drive like a stocker, might even lower cruise rpm and still rip when you want it to go.

There are plenty of cars with 3.23 gears that click of low 12's or better because the package works. Might act a bit like a powerglide, but, so what.
 
This is also one of the things I am doing homework on when putting my engine/transmission/rear end combo together on the Valiant I'm building. I'm not going to to go into detail on my build since this is not my thread, but to help the OP as well; Who do you guys recommend someone contact to build a custom torque converter? Please provide a link, email address, or phone number if you can.

Thanks,
Rob
 
Frank Lupo has good rep.
google Dynamic torque converters for contact info
I use Lenny at Ultimate converter concepts and he is among the best in the business in my opinion.
Also google for info.
You will be a lot happier with a custom converter than an off the shelf , though some companies may have an off the shelf that will work.
But the specifics of your combination make their job easier to get it right the first time.
And quality is not cheap in the converter world , but the difference in performance between cheap and good is worth every penny.

Link to Lenny
http://www.ultimateconverter.com/
 
If the car still has the original transmission, off the shelf converters won't be a worry. Not many out there available for the early 904, so a custom it may have to be.

With the gas pedal floored, the shifts should be 4500-5000 RPM. 1-2 shift at least 35 mph, 2-3 shift more like 70. If you're into 3rd at 30, it sounds like your kickdown linkage is improperly adjusted or missing. It does kick down right? If you mash the pedal at 45, it should lick down to "passing gear". If not, get the linkage adjusted correctly ASAP or your transmission will be damaged.

Is the 273 an original Commando (235hp) or a standard 273 with a 4 barrel swapped onto it? The Commando cars were pretty good performers in their day, and are fairly quick even by todays standards. The car should be able to spin the tires off the line as is if everything is working right. It would help to know exactly what you have (or think you have) before suggesting major parts changes. You may have other problems.

Not sure what your mechanic meant by "adding pounds" to your converter. If he is suggesting making it heavier, get another mechanic!
 
My two barrel cuda spun the tires even though they where crappy tires, were all assuming his car pretty stock if so wouldn't a converter change have little effect with out more done to it like cam, exhaust and gear? Why the choice is it budget? do cam, converter and gear it will make a big difference, my buddy's duster was a 4 gear 318 with 340 top end with headers and the swap from 3.23:1 to 3.91:1 made the hughest difference went from a fast car to an animal.
 
tubtar said:
Frank Lupo has good rep.
google Dynamic torque converters for contact info
I use Lenny at Ultimate converter concepts and he is among the best in the business in my opinion.
Also google for info.
You will be a lot happier with a custom converter than an off the shelf , though some companies may have an off the shelf that will work.
But the specifics of your combination make their job easier to get it right the first time.
And quality is not cheap in the converter world , but the difference in performance between cheap and good is worth every penny.

Link to Lenny
http://www.ultimateconverter.com/
Click to expand...

I was going to mention Lenny but the name of the company slip my mind.
 
Comparing a 4 speed car with a change in gearing to an auto car isn't really valid. A 4 speed car has none of the fluid dynamics or torque multiplication a converter provides. It's strictly a mechanical multiplier.
 
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