selecting a torque converter stall speed



There is a Small Company called Buckeye Torque Converters Grumpy.
They are in Buckeye Ohio.
I purchased one of there custom built torque converters in 2010 for my 1987 C4 vert. 700R4 lockup.
Paid about $325 with shipping.
It has been a Fantastic street performance torque converter.
I just could bring myself to spend $950 for a Vigalnte Precision Purple thing.
What I noticed on Corvette Forum at the time was no one was running real fast with the Purple Thing.
12's with claimed 550-600. Hp engines....
So I thought to myself why should I overpay like all others have and Run slow like them too ???


The guy at Buckeye said his torque converter I bought was good for 700 HP.
No way of testing. Car don't have that much HP.
But the near stock L98 Runs right with Mopar Bob's 2005 Hemi Charger.
Up to 140 mph.


The Grumpy Grease Monkey mechanical engineer.
Staff member
thanks! good info to know

Ive removed near countless transmissions, from cars you don,t need a full lift in your shop,\
Ive done clutch and trans swaps and converter swaps with 4 12 ton jack stands for decades
with these tools.

youll need a quality high lift low profile floor jack thats no more than 3.5" tall flat on the floor and lifts to 20" minimum shop around theres a huge variation in floor jack quality

a cheap but functional tranny jack and 4 12 ton jack stands


you could easily build 4 of these wood jack stand replacements for under $70, for all materials, simply have home depot cut 12 standard 2"x 4" boards into 15.5" lengths and a sheet of 1/2" marine plywood into 15.5 x 15.5 inch squares and obviously buy wood glue and lots of 3" deck screws

Here is a list that I found posted for the trucks that use the 4L80E forChevy.

AVALANCHE 02-03 4 SP RWD/4X4 V8 8.1L 4L80E

C/K PICK-UP 1500-2500 95-99 4 SP RWD/4X4 V8 5.0L/5.7L/6.0L/7.4L/6.5L DIESEL4L80E 17 BOLT PAN

C/K PICK-UP 1500 00-03 4 SP RWD/4X4 V8 6.0L 4L80E

C/K PICK-UP 2500 00-03 4 SP RWD/4X4 V8 5.7L/6.0L/7.4L/8.1L/6.5 DIESEL4L80E

C/K PICK-UP 3500 95-03 4 SP RWD/4X4 V8 5.0L/5.7L/6.0L/7.4L/8.1L/6.5L DIESEL4L80E 17 BOLTPAN

SUBURBAN 1500-2500 95 4 SP RWD/4X4 V8 7.4L/6.5L DIESEL4L80E

SUBURBAN 1500 96-99 4 SP RWD/4X4 V8 6.5L DIESEL4L80E

SUBURBAN 2500 96-03 4 SP RWD/4X4 V8 5.7L/6.0L/7.4L/8.1L/6.5L DIESEL4L80E

TAHOE/YUKON 95-03 4 SP RWD/4X4 V8 6.0L/8.1L/6.5L DIESEL4L80E

VAN FULL SIZE 2500 96-03 4 SP RWD V6 4.3L V8 4.8L/5.7L/6.0L/8.1L 6.5L DIESEL4L80E 17 BOLT PAN

VAN FULL SIZE 3500 95-03 4 SP RWD V6 4.3L V8 4.8L/5.7L/6.0L/7.4L/8.1L/6.5L DIESEL4L80E17 BOLT PAN
and a decent floor jack

to muscle it up into place while getting the bolts lined up

shift kits vary, and transmission shop technition skills are obviously at varied levels if you elect to have the kit installed profesionally, and in most cases , if you have a performance shift kit its not true full manual control, if thats the kit you buy,yes it should kick down, but as always ASK QUESTIONS before you buy any parts or shift kits
generally, full manual control kits will stay in the selected gear regardless of rpm or load, just like a manual transmission, you just don,t have a clutch petal to deal with





even better yet
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The Grumpy Grease Monkey mechanical engineer.
Staff member

HERES A RATHER USEFUL VIDEO THAT SHOWS A 3600 RPM STALL 4l80E stall converter in use

diehrd said:

I hope that link works , it is me driving my vette with a 3600 stall converter . I want people to see how normal it drives and let them judge for themselves with there own eyes.

( PLEASE NOTE ) I am using simple terms I am a visual guy and I am using a simplified way to explain how this works ..

A torque converter multiplies torque until it reaches stall speed and then it works as a fluid coupler taking the engines rotations and turning the input shaft at about 1 to 1 with the crankshaft . I say about because it is not 100% efficient and why a mechanical lock up converter came onto the scene in the early eighties.

The mechanical lock up uses a clutch and locks the converter so every rotation of the crank equals a rotation of the input shaft of the transmission. On modern cars this equates to better fuel economy as no power is wasted.

A few points , to low a stall and a big cam causes lugging or chugging where the motor is being asked to power at 1 to 1 and it is not making any power to do so at a low rpm. GM in the early days of lock up had big issues with this on stock motors because down low they make very little power. As practical experience and electronics came into play GM was able to provide smooth transmission operations and lock up became seamless to the point that today you have almost no idea it is even happening.

On cars like mine where you want power , and daily driving a stall converter becomes your best friend. Even cam makers are acutely aware of the need to use stall converters as well as proper gearing to ensure your able to drive on the street normally .

Remember most driving is below 3000rpm and in most cases we will find ourselves between 1500 and 2500 rpm. That is where the stall really makes a difference allowing us to drive comfortably and normally.

And lastly no stall speed is standard for GM or others. No one has 1 stall speed , it is adjusted per car , per drive train package used. So some thought is used to come up with what will work best.

But please watch clip it shows how seamless and well my car drives with a stout 427 sbc .

thats got to be one of the most common myths out there! guys that have never driven a serious performance car with an auto trans with a higher stall converter have this crazy idea that the car won,t move until the engine reaches the converter stall speed, Ive built and installed plenty of engines with higher stall converters and as long as the rear gear ratios anywhere close to reasonable for the application and tire diameter the converter stalls only real concern you need to think about is that higher stall converters tend to generate more trans fluid heat faster so a good auxiliary trans coolers mandatory if your going to drive around goosing the engine and spinning the tires like many of the guys I build these engines for, (its funny to see 50 -60 year old guys that can afford to rebuild a 440 road runner, or 455 GTO engine with a stroker crank, and these guys still act like 19-20 year old kids once they get access to 600 plus ft lbs of instant torque )
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The Grumpy Grease Monkey mechanical engineer.
Staff member
Hi guys, I am in the process of installing a 582ci shafiroff engine with T400 in a C20 1977 p/u.
I would like to know what diff gears to run as i have 4.11 s and are expecting to have to change.
Also a recommended supplier in the U.S for gears pls as i am in Australia.

This is one area where not doing the math can easily bite you in the ass, vs taking the time to do the calculations ,when you calculate the correct rear gear ratio, the factors I listed , and knowing the transmissions gear ratios ALL come into play when selecting the best match to the engine power simply stated you have a
TH400........with the stock gearing,..............2.48.....1.48....1.0
whats the truck weigh?
whats the tire diameter?
whats the converter stall speed?
WHAT AXLES? (your going to need decent ones once the truck gets traction!
what rpm does the transmission shift at under max acceleration?
whats your intended use for the truck?
and I sure hope you have a decent transmission cooler
theres a whole lot of difference, in efficiency, between selecting the correct rear gear ratio,, example, for a fairly stock TH400 with a fairly stock stall speed converter, even with that impressive BBC engine ,that probably shifts at around 5500 rpm, under WOT, and what rear gear ratio you might want with,lets say a 3600 lb truck, and what you might select for a 4500 lb, vs a lightened truck used for maximizing performance that might weigh, nearer to 3200 lbs, especially a truck with a 3400 rpm stall converter with a shift kit that allows the engine to pull to 6200 rpm before it shifts, that extra weight and /or the extra and higher average rpm band will change the average power band rpm, and the weight will effect how much you can prioritize peak horse power vs peak torque in the gear choice.
its all a learning process, you want too simply want to mentally take a step back, take a deep breath or two,
and start testing to find out whats working correctly,in your current combo,
whats not working up to your expectations,and if its not meeting your goals, logically calculate what should change,
and then calculate what can be adjusted or if necessary parts that can be logically replaced, and re-tested,
if that required too improve the performance.
don,t make the all too common mistake of thinking adding horsepower is the only route to improved performance.
suspension mods, better shocks, better brakes, a stiffer frame, larger diameter and wider tires, and drive train gearing and removing weight,
and correctly setting up the cars chassis to more effectively apply weight transfer ratios,
swapping to lower weight parts,or stronger , or more durable parts, use of stronger drive train components, better matched gear ratios, all help

Runout - runout should be less than 0,25 mm (0,010 inch).

Balance - should be checked with the turbine in at least three positions. This insures that the converter will
not be internally out of balance. Overall balance should be held within 10 grams.

Internal Dimensional Standards:

Fit of pilot bushing
- 0,10 mm-0,20 mm (0,004 inch - 0,008 inch) typical.


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solid fixture here in the forum ... dTNW1fNGFr
What You Need To Know About Torque Converters
What do I need to know about torque converters before ordering one?

A torque converter reacts to engine torque--the more torque you feed a converter the better it will perform. For a converter to operate properly, the engine needs to make as much low and mid-range torque as possible in the same rpm range the converter is rated for. For street engines, this means limiting camshafts to 230° duration at .050" lift, advancing the cam no more than 2°-4°, and using a small cfm carburetor when possible. If the cam is rated at less than 216° duration at .050" lift, you don t need a performance torque converter. Nothing about torque converters is more misunderstood than stall speed. Stall speed is directly related to the amount of torque the engine produces--the more torque, the higher the stall speed. For example, a converter with a 2,800-3,200 rpm rating might provide approximately 2,800 rpm of stall speed behind a mild small block V8, but about 5,000 rpm behind a big block making 800 ft.-lbs. of torque. Without knowing how much torque an engine makes, you cannot know how much stall speed a converter is capable of. While most converter manufacturers list stall speed ranges, those numbers are very general. True stall speed is impossible to measure due to many different variables. These variables include:
Low vehicle weight
Engine displacement
Low compression ratio
Intake manifold type
Carburetor throttle bore diameter
Carburetor secondary linkages
Multiple carburetion
Long duration camshafts

Retarded cam timing t fit their transmission s input shaft. However, since performance converters are built to much closer tolerances than OEM units, the hub-to-input shaft fit is tighter. This often leads people to think the new converter s hub is too small because they are used to slipping the stock converter on without any resistance. Heat is the biggest enemy of a torque converter and transmission. A higher stall torque converter imposes greater loads on the transmission and creates more heat. Thus, a high capacity transmission cooler designed to protect your converter and transmission from heat damage is a wise investment. Finally, nothing beats professional advice when choosing a torque converter. A phone call to one of the converter manufacturers or to experts like Summit Racing Equipment will help you pick the right converter for your vehicle.

one of the very common misconceptions
I hear repeated endlessly is that a higher stall speed converter will make the car used on the street a P.I.T.A. to drive and that if you select something like a 2800rpm stall converter the car won,t move until, the engine rpms hit near that rated stall speed.
the truth is that if you select the correct stall speed for the gearing and application your car will be far easier to drive on the street., it will drive just like a normal car will and it won,t lug or surge like it will with a high duration cam and a stock converter installed
that of course mandates you know a bit about how to select a converter stall speed and match it to your cars power curve.even thought I have a 3200 stall converter the car pulls fine at 1900rpm-2200rpm at part throttle, but no longer wants to jump the car forward and stall the engine when its put into gear like it did with the stock converter stall speed, or bog and not move untill the rpms build
heres my current corvettes 383, its most efficient power is produced in the 3100rpm-6300rpm power band , I selected a 3200 rpm stall and 3.73:1 rear gear ratio, with 25" tire height and the trans shifts at near 6400rpm under wide open throttle

the 383 sbc has 11:1 compression, and this cam, installed 4 degrees retarded and runs a extensively ported stealthram with 36lb injectors and a 58mm throttle body and long tube headers, with ported trick flow heads

notice the power band in theory should be from about 2100rpm-thru about 6100rpm, but the tunnel-ram type intake and extensively ported heads and intake runners and retarding the cam timing move it up to near 2800rpm-thru-about 6400rpm, using a 3200rpm stall means I,m nearly instantly in the power when the throttles held firmly on the floor, and the 25" tires and 3.73:1 rear gear helps







Grumpy, in this post there is a chart with tire sizes on left, gear ratios on the top and yellow, black and blue highlighted area traversing diagonally down to the bottom. What is this chart's purpose?


The Grumpy Grease Monkey mechanical engineer.
Staff member
basically its to give you some basic idea as to what your ball park starting point should be when selecting your cars gear ratio.
the yellow selections are designed more for economy or good gas mileage
selections in blue maximize performance
selections in black are a compromise giving you a bit of both,
lets assume your muscle car has a 26" tire diameter

a 3.07:1 -3.21:1 gears are good for fuel economy but still retains some semi-brisk performance
3.73:1-4.11:1 gears are not great for fuel economy but still retains some, but concentrates, mostly on brisk performance
3.31:1-to 3.55:1 gears are a compromise, giving some of both performance,
yet retaining a bit better fuel economy, that the true all out performance gear ratio selections



keep in mind most performance cars with an auto transmission and a higher rpm stall converter, will need an auxiliary trans fluid cooler, Id strongly suggest you find one with an electric fan and 1/2" or AN#8 line size as you'll want to allow a minimum of 2 gallons a minute trans fluid flow rate

its CRITICAL to keep the trans fluid clean and ideally changed about every 70K miles and use of a auxiliary cooler that keeps the fluid temp under about 170F is going to extend service life a good deal longer
Ive helped do at least 7 of these big block engine swaps now for other people and obviously results vary with the components being used but most of the swaps required a trans cooler and Ive installed 2 now in the rear tire carrier area, 200f -230f temps on trans fluid are very common on stock transmissions, with stock original engines when your beating the hell out of the trans racing, but 190f-210f on the street while cruising is more common using the stock radiator trans cooler in the lower radiator trans fluid cooler.
I had a larger than original capacity aluminum aftermarket radiator most of the time , in my corvette even with the current 383 sbc, and if I ran a 180f T-stat both the coolant and trans fluid tended to run about 190f UNTIL I swapped to a 3200 stall converter , where the temps jumped noticeably by about 20f higher, if I pushed the car ,but those temps dropped rapidly if I was just cruising in O.D. but I felt I needed a better system, to cool the trans fluid, adding the additional rear mount aux cooler drops temps to 150f-160f with the fan on and about 170f=180f with it off even if Im pushing the car so I wired a switch to the fan, and a sensor that turns the fan on at 175F ... -16759.pdf



internal cross sectional area of the fluid transfer lines matters, anything less than 1/2" or AN#8 can be restrictive to flow




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solid fixture here in the forum
S0 just wondering, in this post of yours it says a converter that stalls at a lower rating for less tq will stall higher when given more tq. I was just wondering, my converter stall out of the box was suppose to be 2600, it stalled at about 2500 with my old engine with about 365 -70 ft/lbs of tq, with my new 400 that has about 465-70 ft/lbs I know it can't be exact, but approximately where will it stall now? 3000 rpm? Just curious is all!


The Grumpy Grease Monkey mechanical engineer.
Staff member
the higher the torque the engine produces the higher the converter stall speed is likely to be but its never an exact ratio relationship
if your old engine made about 370 ft lbs and stalled near 2500 rpm, and
your new engine makes 470 ft lbs of torque thats about a 25% increase, in torque.
so you might, quite reasonably expect or guess that the stall speed would jump about 25% from 2500 rpm to near 3125 rpm,
( example 2500rpm x 1.25%-3125 rpm)
While that sounds reasonable, the real world is not as predictable.
In my experience it won,t necessarily jump a totally predictable amount,
simply because there is a wide variation in the torque converter designs,and engine torque curves and cam characteristics, compression ratios, displacements etc.
Id expect it to jump a bit less, to maybe nearer too 2950 rpm from my experience.
this is based on what I've seen when guys bolt the same converter and transmission they formally had behind a performance 350- 383 SBC
behind a new 454-496 BBC engine
ID also point out that occasionally youll find a converter that worked just fine behind a SBC,
fails when you introduce it to a 25%-50% torque increase with a BBC swap
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solid fixture here in the forum
All the Hughes Pontiac V8 torque converters are large diameter
12 inch.
4000 rpm stall even..
High torque capacity I can only assume.

10 inch for Chevy Small Block in general it appears.


solid fixture here in the forum
Coan Racing has the Best prices on 4L80 E Torque converters Grumpy.
I just took a Look.
Have to save up for yet but affordable YES.


solid fixture here in the forum






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solid fixture here in the forum
That is the best price so far Grumpy.
World Famous Drag Race quality too.
Definite going 4L80E in the Suburban.
Do not have to pay $900 for a new 4L80E torque converter for street use.


solid fixture here in the forum
Researching Torque converters for Trucks for Heavy Duty Towing Use today Grumpy.

It seems Heavy Duty Towing Use has unique stall needs.
Turbo 400.
4L80 E.
Reading online the Allison torque converter is used at times with a Turbo 400 Towing.

Looking at your data files.
Looked at the Pirate 4x4.

Kinda neat seeing our old posts.
Always Racing on our minds.