Up to this point, i have always been a stickshift guy my whole life believe it or not (aside from newer daily driver cars over the last 25 years or so). So, i am not familar at all firsthand with the details and habits of converters coupled to street/strip type cars. The car in question is a 73 charger with a reverse manual valve body. I dont know any specifics about it , other than it was built as a pro comp tranny by a guy here on the east coast named Freddy Brown. The paperwork states it is rated up to 650 hp as built. It came with a converter from his shop listed as s/s 3000-3500 stall. Thats it. It is a 10” unit.
It is going behind a newly built 440 based stroker with standard port stealth heads. Dynoed at 629 ft/lb at 3900 rpm and 609 hp at 6000 rpm.
My questions are: this is going to be mostly a street /highway cruiser and raced occasionally at the strip ( a million miles away crom us) a couple of times a year. What can i expect from a converter like this on the street as far as heat build up, issues, problems? Also highway on longer drives, will a typical converter like this build up too much heat with slippage? I have a nice b&m trans cooler mounted in front of rad isolated and i run the slightly deeper steel pan with extra quart capacity. I took off the real deep aluminum cast pan after i cracked it open in I78 on the way home from Carlisle a few years ago. Thats another crazy story!! Anything else i should know or be aware of?
Once i get the motor in, in a few weeks, i can test stall to see where we are at, but just ideas and info in general right now would be very helpful to me.
Thanks fellas.

Sounds like it should be pretty dialed with that 10". They act a little slippery but drive and shift it just like a normal auto would shift. That is, never shift down unless there is throttle pressure. They can build some heat but cruise nice. I take it you're not climbing any mountains with it in New York?

It'll be fine. W/ a cooler like you have, there shouldn't be any problems at all. Don't know him, but had Freddy Brown powerglides in a couple of grudge cars I helped my NY friend with. Seemed to be good stuff.

If I were the “project engineer”, in basic terms.........it would get as tight of a 9.5” or 10” converter as one of the more respected companies would build.
With that sized converter, behind that motor, in that weight car, with real street gears(3.23, 3.55, etc)........ even a really tight 9.5-10” unit will still stall at 3500-ish, or more.

Most off the shelf street units aren’t designed with 600+ Ft/lbs in mind.

If it wasnt built specifically for a stroker with that kind of torque, I’d just send it out now and have it adjusted before I bothered putting it in.

What gears? Was the converter built for a stroker or for the 440?

Unless it was built with 600+ ft of torque in mind, I guarantee you it will flash much higher than 3,000-3,500. These torque monsters absolutely require a converter made just for them.

Before you stick it in, I would suggest that you find out all you can about who built the converter and to what spec. I have had my share of struggles getting a good converter for my street/strip strokers.

In case you need to make changes, it is much cheaper and easier to do it now. Lenny @ Ultimate finally got me a really good street/strip converter after several misses from other converter builders including PTC.

it will flash much higher than 3,000-3,500
I agree

My experience with converter companies is that they can not predict how their finished units will perform. In the last 4 years I have filled out the forms for several major companies, and provided time slips, dyno sheets, and all the engine specs, everything they asked for. Not one of the companies spec'd the same size or type of converter, at over $1,000 I expect better than an educated guess. If the companies had it down to a science then I should get similar combinations from each company right? I have had several companies spec camshafts for example, and they almost always give me very similar choices. If you want the best performing converter be ready to buy and try several to get one that works with you combination. Just my experience.

If you value street drivability more than best ET,then a tight converter, similar to what a stock 383 roadrunner converter is, will be a good choice. The car will move out smartly when street driving without a lot of rpm, but obviusly more than a 383.
I have a 10 inch behind a 408 in a light Dart, supposed to be tight, flashes too high (4000) and feels like mush. Don't get me wrong, the car is very quick, i just don't like the loose feel. Many years ago i had a stock Hemi converter behind a 535 inch stroker, worked great for the handful of runs it survived. I think those converters were VERY similar to the 340 and 383 stock performance converters.

Yep, and forum advice can be just as bad. Converters are black art.

Find a GOOD converter company and give them GOOD quantifiable information and they will get it spot on. Give them inaccurate pie in the sky numbers and info then they will not get it right.

Yep...smae UCC converter in my car for 12 years. I have made some changes and it's been fine...but...I may send it back this year to have it massaged a bit for the extra HP this motor makes compared to the rest I've had in the Arrow.

Thanks for all the good info and advice so far. The only other info that i can think of is weight is 4240 lbs with driver. Rear gears will be 3.23 for street/highway trips, and 3.91 for track. 8-3/4 rear. I will be running drag radials 28 “ tall.
Only actual numbers i have are dyno numbers. They are as follows:

Rpm. Tq. Hp
3900. 609.7. 452.7
4000. 608.3. 463.3
4100. 610.6. 476.7
4200. 613.1. 490.3
4300. 621.1. 508.5
4400. 625.5. 524.1
4500. * 629.6. 539.5
4600. 628.6. 550.6
4700. 625.4. 559.7
4800. 622.0. 568.4
4900. 619.1. 577.6
5000. 616.3. 586.8
5100. 611.7. 594.0
5200. 605.8. 599.8
5300. 599.4. 604.9
5400. 592.6. 609.3
5500. 581.4. 608.8
5600. 571.2. 609.0
5700. 561.3. 609.2. *
5800. 550.7. 608.2
5900. 540.3. 607.0
6000. 531.3. 607.0
6100. 515.7. 600.6

Avg. 602.07. 559.43

So, peak torque is at 4500 rpm. Does that chang anything? I guess for strictly racing, i woukd want a 4500 stall, but for combo driving, what woukd you guys be looking for? Aside from calling and having one built, or my 10” adjusted. I will do that, but trying to understand the fundamentals and theory of it.
If i can think of any other info, ill add it

what cam is in the motor?
does the motor have a 4.25" stroke?

If you already have the stuff, just send it! That kind of power overcomes a lot of things that aren't perfect. It will be ultra fun to drive. It will use a truckload of gas.

If that converter wasn't built for the level of torque his motor is putting out won't it cause the TC to stall way too high? Sounds like the issue I was having towards the end of last season. I have a 10" converter that was built for use behind a small block and I when built the 512 I reused it. Chassis dyno results were lackluster as the torque curve wasn't flat at all behind the peak number. Still hashing it out...

Really nice looking power curve😎

You really don't need to fill out a tech sheet for this application. Just have the converter built as tight as possible. With over 4,000lbs, 3.23 gears, 600+ lbs of torque, and street driven, you can't get it too tight with the 10" converter cores available.

Now, if it were a track car trying to hit the number, it would be a different story. But being primarily a street car, it won't be too tight. In fact, I would be surprised if you can get a converter that would flash below 4,000 with that combo and a little traction. I haven't been able to.

Put it together, enjoy it, fine tune it later if you start chasing ET's.

FWIW, I daily (couple times a week anyway) drive a car with a converter that "flashes" to 4,100. All the control is under your right foot.

It does have the 4.25” stroke. The cam was speced out by “The Wizard” Dwayne Porter. Well thats what i call him. Thank you Dwayne!! It is a solid roller with lift of .577 / .583 and 248 / 254 @ .050

So, i could do that... just put it in and run it till the summer and see how it feels. Then, if no good, i can have it reworked. I guess, does that mean if i call a converter shop, they will accept and adjust a converter that was not one of theirs? Or they don’t like to touch someone else’s coverter they didn’t build?

Also, from what i gather here, if a high quality converter maker designs an optimal converter for my package, it would perform optimal at the track as well as being as efficient as possible for street driving? Im not sure how they both come into play together.

Ultimate tightened up my PTC converter. No problem. And was much cheaper than a new one.

The goals of a race converter would be different than those of a street converter. So there will be differences. That doesn't mean that a converter can't be dual purpose, it's just that they will have different characteristics.

Asking about street vs strip converters is like asking what's a street car.

The converter for a street/strip car is like essentially every other part on a street/strip car.
It’s a compromise........ like the cam, carb, rear gear, etc.
Most of the time the decisions for those parts are based on balancing the cars performance with the drivability on the street, along with reliability and how much street use vs track use.

It often works out that chasing a tenth or two on your street/strip car can cost you a disproportionate amount of lost street friendliness.

As I said previously, and reiterated by Dave........ you basically want as tight of a 9.5” or 10” unit as can be had, and it will still have over 3500 flash(probably closer to 4000).

“If it were me”, I’d send the one you have to Lenny at Ultimate, have him cut it open...... and then have a talk about what can be done with it.

If it’s not up to the task of 600+ ft/lbs, and it fails......... that’s more problems than just needing a different converter.
It’s a trans full of metal.

4240 lbs, 68 Charger in your signature ?? how did it get so heavy, mine has d60,a518 overdrive, A/C, everything there, glass hood,4050 with me. Get your converter looked at, I had to get a custom TIGHT 10" converter built for my 512 street car, will flash 4k, but drives good on the street 3.54 gear.

Ok, i understand. Makes sense. Thanks

The car this is going in, is my 73 charger. It also has 71 grill with hideaway headlights, so that doesnt help either. Last time at the track on the scales with a completely stock 440, it was 4360 with me in it. So, im guessing at the weight with this motor and all aluminum parts swapoed onto it including headers for the ex manifolds. I figure around 4250 or so

I run a Luppo Dynamic 9.5 converter in my 63 and they call it a street/strip converter and it was made to flash about 4200 behind my old 440. I now use it behind my 493 and it will still flash from about 4200 to about 4500. And I love it as the car drives around on the street like a normal stock type converter as I don't feel any slippage in it driving it normal. And it works fine at the track. I don't set the world on fire but it has given me a 1.50 sixty ft in my 63 at close to 3800 lbs and on just SS springs. You should be fine and as said as long as you have a good cooler it should work and drive fine. My converter has been in my car since 2006 with many street miles and some drag racing and it still drives great and works fine at the track. Good luck with it. Ron

T

Thanks Ron. I’ve always loved your ‘63. Great running street strip ride. Im gonna try to call Freddy Brown and find out what converter he used and if he has the specifics on it. Then, i can send it out for adjustment if i need to.

Thanks for the kind words as I also love that 68 Charger of yours that runs so good ! I would think any good converter company today should be able to build one that works good in your car on the street and the track. Ron

I had a Dynamic Converter for my 727 in my 440 GTX, and was very impressed with it...just did not like the 727 because it had a manual valve body.

I just ordered a 4l80e and a Lock-up converter from Sean and Frank at Dynamic...I trust them since they build great Converters and transmissions.

One thing that is important, is to give them the exact application, weight of car, HP/Torque, Cam, Rear Gear so they can build a converter that really is what you want. I have fudged before, and you get what you order...

My race days are over, but I still want a street/strip car that will be fast, but street friendly.

Mark

Thanks Mark. Ill be sure to give them all the info i can.

Can anyone go into some detail, in laymans terms (haha), what they actually do to a quality built unit, compared to a unit that is not as efficient at the track. Also same question for a street speced converter. And finally, the diff internally between a converter more geared to the track than the street. What is changed internally to change the characteristics. I know the general parts inside and terms. Thanks