I just added a Gear Vendors to the Charger to tame the 4.10 gear for highway cruising. The rpms now equal a 3.23 when in overdrive.
I have a 440/493 with 10.8 to 1 ratio, Edelbrock heads, the MP 292/509 cam and TTI 2" headers. The converter was locally built, it is 9 3/4" and estimated to be a 3000 stall. I'd say that the estimate is pretty close to that.
The PROBLEM? While at cruise speed, the engine runs UNDER the stall speed and feels lazy. The 4.10s have a whine and I want to swap in a known good 3.91 SG chunk, but that would make the cruise rpm even lower. Normally that would be a good thing interms of improving MPG, but as it is now, the trans slips up to and above 3000 rpms before feeling much acceleration. I'm in a tough spot though. I want LESS stall speed to improve freeway performance, but it needs to have enough stall to keep the car from being a slug from a dead stop. I don't plan to drag race the car much, but I DO like to boil the hides on occasion. I guess this leaves me in a tough spot, since the MP '509 cam seems to like a looser converter. I do intend to move up to a Comp 285 cam. I ran them before, but both wiped a couple of lobes within 500 miles. Since then I heard that they have improved their products. Also during that time, I learned more about proper oils to use to avoid failure.
So in summary, Does anyone have advice or experience with this? I'd like to lower the stall to 2300-2500 but would like to hear from others. Thank you, Greg.

Sounds like you want a lock-up converter. We use to call the old GM lock-ups "dial-a-stall" do to certain mods. Maybe something simular for Mopar?

You have bolted together an pretty odd mix of parts.

The cam will not like to run happily at low rpm but you desire the low rpm for cruising.

Today's answer would be a broader range camshaft profile. Less overlap. Something that will run well, just off idle.

The cruise rpm under stall speed. Again, in a modern car. The answer is a lock up convertor.

I was able to experiment with this with a 518 lock up 4 speed automatic.
My conclusion was the manually engaged lock up was more useful at low rpm. I could engage lock up at 1700 rpm and pull 500 rpm out of it. Lock it up at 2500 and it would only pull 200 rpm out of it. At 3000 rpm, lock up vs no lock up was hardly noticeable.

Try comparing you cruising rpm vs cruising rpm on jack stands. What is the rpm difference? Alot says it's really slipping. None means, I wouldn't worry about it.

Do you have a trans-temp gauge? I'ed be worried about it overheating.

I have a OD trans in a brand-X car and it has a loose converter and lockup. If I forget to turn the lockup on it gets real hot.

If im on the highway cruising along there is almost a 800rpm difference between on and off the gas just maintaining speed at 55mph.Its just sitting there heating up.. No get up and go until I push on it more.

Click the L/U on and the temp drops off and its like a manual on the highway. Instant response.

I think you'll need to have a new converter built. You'll have to see if one of the big converter companies can build you a converter that will flash stall to 3000rpm when you nail the throttle from a stop, yet not slip so bad during normal driving. You're not the first guy to put an overdrive into an old car so I'd think the converter companies must have some experience with this. I would be expecting to shell out another 6-700 bucks for a custom converter.

Today I went to the local company that built the converter. The man said that he could cut this one open and change a few things including the stator to change the stall speed. I just wonder if he can take 500-700 rpms out within the same shell.
The one snag may be if the parts inside are already at the low end of the stall rating. That would mean a whole new converter.
You're right... I am not the only guy to add overdrive to a lopey cammed big block car. There must be a solution somewhere.

I have a very similar engine setup, and similar goal to keeping the RPM's down, but with a 4 speed. When I changed from a 4.10 to a 3.23, it was like losing 100 HP and the low RPM (city) driveability suffered terribly. I called Racer Brown with all my specs and he ground a SSH-25 cam (.485/238*) for me, to replace the STH-42 (.520/254*). It made a lot of driveability difference, but the power loss was still there. I just sent a spare vacuum advance distributor to 4secondsflat for rework (currently have a tach drive distributor installed). Hopefully, that change will get me back where I want to be. If I had to do it over again, I think that I would go lower on the compression and use a cam ground similar to Cadillac 500 CID specs.

The kinda coin being talked about here, I'd personally go with the lock up in the OD trans. If I was closer I'd roll up my sleeves and give a hand

I'm not against spending money, but I already have a perfectly good running rebuilt 727 with the Gear vendors unit. Too much money tied up in these two to just walk away. If I was starting from scratch, I'd tend to agree with the 518 crowd.

You need to call Frank Lupo's Dynamic converters.

http://dynamicconverters.com/news.htm


They will hook you up with what you need. I have a 500 Stroker, 727, Gear vendors with 3:55 rear. I have driven it over 50K miles in 8 years. In 2008 I switched from a Mopar Performance 175K to a custom converter from Dynamic. The difference was night and day. MPG increased by 2. The car idled and took off way better than before. The converter flashes to 3800 when I need it to. No slippage on the highway when cruising at 75 MPH at 2500 RPM. No slippage from a dead stop either. Cruising at 35 mph in OD, punch it, converter flashes to 3800, my 4200 pound car takes off while whipping my passenger's neck back into the seat.

The original 509 can be driven on the street. I got 35K miles and over 100 1/4 mile runs on mine with the GV in the car before it wiped a lobe. Went with a little milder cam on the rebuild.

9.5 Dynamic here in a 3600 68 Sat. 3.23 gears. Flashes to about 4500 behind a mild 440. A little spongey maybe, but not bad at all. Been in the car about 10 years and driven often. I don't think you mentioned whether you have an automatic or manual valve body . I can imagine that an auto valve body that shifts early might feel lazy with the converter i have.

What would be the downside to running a factory 11" converter? I know that stall speed is relative to an engines output. More specifically, an 11" converter behind a 318 will stall lower than behind an engine like mine. Since I'm not a hardcore drag racer, losing a little snap from a dead stop is a fair tradeoff.
Opinions?

A 440 with a 509 cam and a stock converter would be a dog. But with yours being a 493 and a 4.10 gear, it might be doable.