Cam Duration and Stall Converter...do I have enough?

allcarfan

The Answer Man
Founding Member
Apr 8, 2001
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North Atlanta
I have a stall converter from TCI that is suppose to stall between 3000-3500 RPMs. My car weighs in at around 2700 pounds with me in it..

Cam duration is: Duration at .050 in.: 232 intake/240 exhaust

Do I have a loose enough converter for this? I have 3.50 gears with a C4 Transmission


Thanks
 
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Plenty.
Maybe a little too much, if it stalls that high.
The car is on the light side, the CID is relatively small, and the gear is relatively tall... so you will stall on the low side of the verter's range. That is probably a good thing.
If you don't drive the car all the time, have you thought about a lower gear? 4.11s would be awesome with that combo.
Don't get me wrong though... 3.50s are good, you have added some cubes to the engine too, so they might be perfect. I am going by my setup, similar, but only 306.
Dave
 
Thanks Dave.

The stall is rated at 3000-3500. I figured since the car was so light that it would stall probably round 3200 or so. I dont drive the car all the time, but it will be on the highway from time to time and I really dont want to cruise at 3500+ RPMs with 4.11s :)

The ci is 347 and the engine should make a HUGE amount of torque. This is just a fun car, not a racer, just something to cruise in once in a while. MAYBE take to the track for giggles.
 
You probably won't like this idea, but the more I think about it, this is how I am thinking.
I think you need more gear, not less stall.
The idea that you will be cruising under your stall speed is something that didn't cross my mind. This will burn up your tranny due to excessive heat and slippage.
You could go with a lesser stall converter and be okay, but that converter will come in under the rpm where your cam starts making good power.
What I am getting at is that the converter change is a compromise and band aid, while a gear change puts all components in the combo on equal terms and makes it the best it will be.
Don't get me wrong, a lower stall will work.
Dave
 
70 mph is about 3170 with 26in tall tires. It already won't be fun on the highway. Converters are usually optimistic (don't stall as high as they say), and 2700# is on the light side, so I would try it, you might like it.
 
It would help to know.

tire size:

exact cam specs (Whose cam? What converter did they tell you to run? What is the "mimimum" rpm?)

expected torque curve of the engine.

I'm inclined to say try it and see how it works but be prepared to change the gear. A 3.73 or 3.90 gear would raise the cruise RPM several hundred rpm (each step).

If you are absolutely not going the change the gear, and you think the cam will be making good torque at 2500, then yes I'd probably change it to a 2500 stall.

IMHO
 
i say stick with what u got. it should run some good times. if it is an everyday driver then go tighter, but for et stick with it. I ran alot less cam with a 3000 converter and it worked great at the track. Did fine on the street but it wasn't an everyday driver either.
 
I really dont want to change my rear gear. I just finished having my rear end built, its in the car, nicely painted, everything torqued down, plus, its a big added expense. I can swap the converter relatively easily since I will be pulling the engine out pretty soon.

A friend of mine has an 'E' cam with an AOD and a 2800 stall. His car is pretty heavy (84 vert). He has no problems on the highway, but in town, he cant get the darn thing out of third gear.

Looks like im getting all kinds of different opinions on what to do with the stall and gears. Tough decision- although...some 3.70 gears....

damn, why did i even post this thread? LOL
 
brianj5600 said:
70 mph is about 3170 with 26in tall tires. It already won't be fun on the highway. Converters are usually optimistic (don't stall as high as they say), and 2700# is on the light side, so I would try it, you might like it.
I run 3.80 gears and I'm about 55at 3100. I honestly would keep the thing just the way it is. The lower gear will make the car stall a little higher, especially with the torque from bigger motor. I have the same stall in a gutted 67 with a 302. I tried the 2500 from TCI on the advice from Summit. Huge mistake. It was too small. This stall is for the street. It isn't real loose. So it actually drives nice like a stock stall on the low end. My car creeps forward in drive. I have over 360 ft/lbs to the rear. A 342 will like the stall I think.
411 is right in that the gears may put you a little under the lock up speed. But... the stall is not a full lock-up, and if you have a tranny cooler it will be fine. Mine was for 2 years in 100+ heat in the desert. Also with no serious load on the stall it will lock up a little earlier. If it was the full blown type of stall where your car doesn't move 'til you hit 3k, then I would definetly worry about heat.