Technical what stall converter in 31 model a ?

I have a 31 model a truck with new engine going in,need converter stall help. Specs on truck are 2600 lbs with me in it. 355 chevy about 360 hp. 2.02 1.60 valves 9.5 compression 600 edelbrock air gap intake. 1.5 roller rockers. cam is a roller with 284 adv. duration .480 lift transmission is th200r4 lockup. rear gear is 3.42 with 28 inch tall tire. Lake style headers dual exhaust. I cruise the interstate alot. Truck sees about 7000 miles a year. hughes tech line suggested 2800-3000 stall. I was thinking 2400. My concern is the weight. It is light so maybe better with higher stall? I'm getting the transmission rebuilt . They said i should have the trans rebuilt without the lockup . Thoughts? Older pic of truck

 

I think your Rite on in 22-2400 range, Because it's light

 

I thought that for interstate cruising, you'd *want* lockup.
What's their rationale for recommending no lockup?

 

Lockup makes the trans run cooler and drops rpm too

 

How often do you put your foot down all the way?

 

The wife says alot. lol I really am not concerned about performance. mpg not so much. I just want it to idle right and be driveable. She takes it to town shopping. When she drives it stays about 55 mph unless on the interstate, then its 70. When i drive on the interstate i run about 75 to 80mph

 

Its light and you don't have much cam. A stall just slightly over stock will get ya where you want to go. 1500-2000 is what I would be looking at if I needed to buy one or stock would work too the 200R is already loose until it locks up.

 

Best A to Q,I see is porknbeaner's. others are fine in there ways.
Way too many guys fail to know that it's more about a good idle RPM ,that your engine can do,then how light your car is.
If engine can still idle at factory stock RPM well,you can use a stock set up. No matter what you use,lighter cars need more brake at a stops.........

 

What's the RPM at highway cruise speed? Keep the stall speed below that to keep heat down. Use an inline trans cooler.

 

Duration @ .050?
Using the lock up, you could live with a 26-2800 stall speed, but you don't want it to feel mushy around town.
Important thing it to stress the light weight when ordering a converter. Talk with a smaller, hi-po builder. Avoid an off the shelf piece IMO.

 

EXACTLY.... RPM at cruise speed on fwy -300/500 rpm +/- = stall speed... My model a sedan, big block power, light like yours is; I started off with 3k stall, built up too much trans heat to feel comfortable, swapped to 2600 Hughes stall and was a tremendous difference... Hughes makes a great product, just set your stall speed under highway flying and you keep the trans happy for sure.

The key is light vehicle with good power can pull past a tighter converter.

 

Rpm at 75 shows 2300 in overdrive. No lockup. So I would need lockup on interstate. I could try stock I guess. If I don’t like it go with 2400 stall. Worried most about around town. Idling at stop lights. Also heat buildup on highway. Not racing so keep it simple. If I want to play bump up to 3000

 

So if this is a mostly street driven car with no or limited time at the drags, than I would say ~ 1800 - 2200 stall speed is where you want to be. No reason to go 2400.

 

So if i use the stock converter it should stall a little higher with the bigger cam? More torque more stall? If it stalled at 1200 before it should stall at 1800 now. I am going with stock and see what happens, it's easy enough to change if i feel the need. A 2400 or above would put into power band quicker but not needed. I hope this thread helps others also. Lite car , more power yet streetable. I know cam and converters need to be matched, i just want to get it right. The old days when i had heavier cars 3000 lbs plus i would have went with 2400.

 

Check my math here.... a 3000 stall converter in a 4000 lb car is one thing, put that converter in your Model A weighing 2600 lbs and it will hook up at a much lower rpm. It might be just what you want.

Also, I’m not sure why someone would recommend ditching the lockup converter. They work great in a street car.

 

Well, that maybe depends on your definition of stall. I can give you 3 definitions:
1. The highest rpm the engine can attain before driving through the brakes
2. The highest rpm the engine attains under full throttle acceleration from a slow speed while the converter is slipping
3. The highest rpm the engine attains under full throttle conditions with no output from the transmission output shaft (probably requires a trans brake).

What are you referring to when you say "Stall Speed"? I believe that with #1 & #2 the stall speed will be lower than stock. With #3 it will be higher. But you may get a disagreement from some others.

Reference: https://revmaxconverters.com/part-i...Z1UqD_HVUkDTw7tUR09B_a5ILCVDzkXBoCRnYQAvD_BwE

 

I get that and 3 is probably right. I don't care what stall speed just driveable. stall speed not important unless my car won't idle low or creeps forward. If it stalls at 100 rpm i don't care. If i wanted to take off fast it would matter. I care if i was to use a stock converter and really needed a 3000 stall. Just wanted to do it right the first time.

 

Put a 5.0 HO and C4 in my '31 and went with a 2200 stall converter. Turns 2400 on the freeway, trans stays cool, life is good.

 

So as @Mark Yac said, talk to a builder, tell him what you have and what you want and have him supply one to meet your needs.

 

If overall driveability is important to you go with a stock converter. A "loose" converter (higher stall) is a PIA around town - the throttle delay and lack of engine braking will drive you crazy - and will "slip" more on the highway. The only possible drawback is if you must run a high idle speed because of a cam the car will want to "creep" when stopped at lights. You'll just have to hold it by applying a little more brake pressure.

All the claptrap about the advantages of a higher stall converter only applies if you are building a race car. Otherwise take advantage of all the research the factory did when designing engine components for every day driving.

 

talked to hughes and they said up to 3000. Thanks to the replies here i'm going with stock and see what happens. less heat as long as it works. Most here say 1800-2200 which keeps me below my cruise rpm on the highway so less heat buildup. I will keep the lockout. I also have a cooler. Thanks for the help

 

Driving numerous pre 40's cars thru the years I wouldn't build one with a nice v8 and decent cam without at least a 1800 stall.

It drives me crazy to get a nice rod in the shop to work on and go drive it and the damn thing tries to push itself thru a traffic stop. The lighter the car the worse it is. Car doesn't have enough weight to hold the front tires to the ground so it just pushes them thru the intersection.

P.s. one of the reasons racers went to trans brakes instead of line locks.

 

I run a model A coupe with a sbc 355 with almost identical specs to yours. The only difference is 4:11 gears in mine and a 700R4 trans. The cam manufacturer recommended a torque converter with at least 2000 rpm stall speed so I installed a 2400 stall speed unit. It is about right for this car. It still pushes slightly while idling at the streetlight and hooks up right away. I think a stock converter will try to push you too hard at idle and that is a pita. Also, because the car is so light, the converter tends to hook up before reaching the advertised stall speed.

 

What rear gear are you running?

 

I ran a B&M 2200 stall convertor in my 2600 lb. Morris Minor . It had a H.O. 5.0 with an AOD and a 4.11 gear.
I ran external cooler and a transmission temp gauge . On the highway/interstate it turned 2300 rpm's at 70 mph. Trans temps never exceeded engine oil temps.
I had a lot more cam than you have and never had a creeping issue at a stop light.
I had a non lock up convertor. Before I went to the 4.11's I had a 3.00 gear and in town I had to pull it down to 3 rd or it would hunt and lug the motor.

 

Started with 3.89's and was running about 2700 rpm. Changed to 3.25's and rpm dropped to about 2400. Almost unnoticeable decrease in takeoff from a dead stop, but it would be more noticeable with a heavier car.

 

As asked by the man that competes in the power tour... "Every chance you get"! Hahaha

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Use real inline oil cooler... With radiator fins in conjunction with the radiator! Those aluminum tubes arent enough!

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I ran a 2400 stall in the turbo 400 behind my 500hp 383 in my Camaro. Never any issues and had great street manners. Have the same size converter in my coupe now. All you need


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Creeping at a stop sign is a result of too tight a converter for the engine, rear axle ratio and drive axle tire diameter you have, NOT the vehicle weight. This is true unless the area you are stopped at is not level but an upward slope, in which case gravity and vehicle weight can be considered.