Torque Converter (Proper Stall)

[Markcuda]

Well guys I'm new at this website so bear with me please but what I've seen is a wealth of information.

I have a '69 Barracuda with a 904 auto., I'm going to install a 360/380 crate motor this winter, 750 carburetor, CPPA headers, my question is: What stall speed torque converter should I use? My rearend is a 7 1/4 with 2.76 gears but this is not the gear or rearend set-up that I plan on staying with. I'd like to go to a 8 3/4 with 3.23 gears. So the torque converter that is good for the 2.76 gears, would it also be good for the 3.23 gears or could I just use my stock torque converter? Any advice on this matter would be very much appreciated. Thank you in advance. Mark Smith

[fox]

I would figure out what rpm you are running at 60 and not go over that for starters, because, for a street car it will slip a lot.
Change the gears first. You may find that what you have is fun, a too loose converter is not fun on the street. However,you will find that the stock converter is not stong enough for serious street bashings with sticky tires.
I will tell you to buy a good name converter when you do buy. AVOID TCI. I have never had success with tci. 3 purchases and 3 disappointments. And they new the vehicle specs.
I see that we are near each other. I have a 3.23 center section ready to go, if you are interested.
Fox

[Leigh]

That engine, from my experience, (a friend has one), needs quite a bit of converter. However, running that high of a gear, (not trying to be obstenate, but I don't think you will like it), will add some flash to whatever converter you choose. Give you an idea, his package, 73 Challenger, completely stock weight vehicle with, 10" 3500 TA, 4.56, 904, BF Goodrich Drag Radials, same engine and carb only with Hooker headers, is a stone launching. I've been on him for 2 years to up the flash to 4500 to get up on the cam. This is 50/50 street/strip. Runs 13.0's. Should run 12.60's. Your package is lighter, and could be faster. I personally (don't you love opinions!) would run a 3.91 or 4.10, with the same converter my friend has if it is going to be street only. Good luck, have fun$!$.

[Dart_340_Swinger]

The mopar crate pushes about 400horse! A friend of mine has a chevy that makes 375 horse w/ a race TH-400 trans, and a 12-bolt 4.11 posi rear! The trans shop around here is nothing but high-performance and he recommends a 2500-2800stall for that! He also told me he recomends a 3500-3800 stall for a 502ci pushing 450 horse! If you have a higher stall it will just cut performance!!!!!!!

[Comp Chassis]

The 380 crate motor is going to be a pig on the bottom end with a 3.23 gear and too little converter.

I dont know how much highway driving you do, but I would recommend at least a 3000 converter with 3.55 gears. If you do very little highway driving, I would suggest 3.91 gears.

With 3.55 gears, at 60 mph with a 3000 converter you will be close enough to its stall point that you wont cook it.

[Markcuda]

You guys are a wealth of information. I never expected this many replies in such a short time. I'll try to be more specific.

The reason for the 3.23 gears is I like to do alot of highway cruising. At 70 mph and a 5.0 boy comes along side, I want to be able to follow him to the end of his speedometer not mine. With that much horsepower and cubes, I don't think a Cobra Mustang will be a problem. I guess what I'm trying to say is, "I like to stretch my legs". Probably more so than the 1/4 mile. I'm going to have a shift kit put in the transmission. I don't think I need to bullet proof it because I just don't see myself hammering it on a day to day basis. But I'm sure my 7 1/4 won't last long but I hate to spend the money before I destroy it. You guys are great. I just hope this project turns out the way I have thought it out so many times in my head.

[Streetwize]

The type of converter you use is just as important. A Coan w/2600~2800 stall would work great. An old 340 high-stall would work better than just about any TCI or B&M I've seen. Tire size has to figure into your stall and gear slection as well. You don't want to go too high, you don't want that slipping clutch feeling at low RPMs (no fun and lousy mileage is what you look forward to) The heavier the car the worse it is. The 380 crate motor, even with a 240 @ .050 cam has decent bottom end, it can be made noticably better with a set of Crane Variable duration lifters; better off idle to mid range=lower stall neccesary. I think a set of 3.91's with a 275/50R15 BFG would work pretty well. I think they'll fit a 67-69 with the right wheel offset and S/S springs. Put in an 8 3/4 w/moser cut truck axles. You can also pick up substantial drivability and off-idle torque by tuning your Acc. pump shooter size and cam if you have a Holley. I'd start with a "31" long barrel shooter and a pink cam in #2 position to start. you'd be suprised how much difference it'll make. I'd optimize this for youe present set-up before eventually swapping out the converter.

Wize 1

[Streetwize]

Oh yeah, one more.

Unless you go 3000 stall w/3.91 or deeper gears, you'd be a little quicker going to a Performer RPM dual plane over the M1 single plane. The top end power is almost as good (especially when running a full exhaust), and your torque (momentum) at launch and at the 1/2 shift revovery rpm will be better which means your e.t will be quicker and your MPH will be close.

okay...I'm done

Wize 1

------------------
Streetwize

[rb77413]

I have a 70 Newport with a mild 383, 3.23 gears, and a 2500 stall. The 383 is about 9.5:1 mild head work mainly polishing, Performer intake, Hooker C-Body headers, 2 1/2 exhaust with glasspacks right before the rear tires (like the T/A's) Edelbrock 1411 (750 elec choke) A stock tranny. The rear tire is 215 70 15. Since my van went down the Newport had to double as tow vehicle. With this heavy of a car the converter goes all the way to 2500. Light throttle driving and at a stall of 2200, I start pulling from traffic easily. With a little more throttle to get to the 2500 stall the guy next to me has to try to keep up. Any more throttle and not much normal cars (Honda and the likes keep up). I keep up with traffic no porblem with the trailer on the back (1900 lb). I actually think the converter is a little loose for highway driving. It turns about 3200 @ 80mph. Another Newport I had stock 440 2.76 235-70-15 did 3200 @ 100. If I was going for top end, maybe a 2200 or 1800, with the 3.23's. I like the low rpm pull. I'll hit 60 in first at 6000 with the 383. It is neat to break just about any speed limit in second gear The only thing like said before, is if the crate makes enough low range torque. Smaller primarieson the headers might help but you'll probably lose upper rpm power a bit. I'm still getting used to 2500 stall converter I got. As a note I got the converter from www.mopartsracing.com for about $155. It is a rebuilt converter though. I have no problems with it. Good luck on the final decision.

Bob

20 MoPars and countin'

[Leigh]

No matter which converter you buy, make sure you can have it adjusted at least once. If you make it tighter than 3,000 (my opinion thats too tight, unless you use that 3.23 which will make the converter see more input load) you're gonna be sending it back in to be loosened up. We're concerned with flash guys, stall means nothing.

[72Challenger]

Hey, Mark. What do you mean, you want to be able to FOLLOW the Muststink? You've got a Mopar, he should be following you!

Seriously, I know where you're coming from. I like top end too, only get to the strip about twice a year. If you're talking about a roll-on contest starting at 70 MPH, then converter flash and bottom end is meaningless. A looser converter means more slip, more slip means less top end. You don't give your tire sizes, so I'll guess at 245/60-15. Check this out:

At 70 MPH with a 3.23 and 26.5" tires, you'll be turning 3010 RPM with a 5% converter slip. Alongside pulls the Cobra, wanting to race. You give him a length and then floor it. You'll downshift and jump up to 3960 RPM. With the crate engine, you're now over 400 ft./lbs. of torque, and only 400 RPM below the torque peak. Now run it up to 6000 RPM. You're doing 140 MPH in 3rd gear. You may wind that engine up a little tighter, but not for long! Now see what a looser converter with 8% slip will do. At 70 you'll be turning 3096 RPM. Downshifted, you're at 4490 RPM. Yes, you're accelerating faster than with the tighter converter, and you top out at 136. So you think the 4 MPH doesn't matter? Consider this. Your converter will be slipping like crazy all the time under 70 MPH. I wouldn't recommend anything over 2500 stall for this reason. Now if you move up to 3.55's, this changes everything...