I got a 355 vortec supperram and I have a 3000 stall converter tucked in a 700r4.. Besides gettin the short end of the stick on mileage, its not shifting quite right. Shifts a little late and my rpms stay in the 2400 hundred range under a normal load. I remember how the original 305 tpi shifted with a normal torque converter, its jus not the same.. Can someone help me out please??

 

What cam are you running that would need a 3000 stall? Is the converter a lockup type? Have you properly adjusted your TV cable? Higher stall converters slip more at lower rpms so that's why you're seeing the rpms stay up just driving around. They drive quite different from stock tight converters. My 4,000 stall around town hovers around 2000-2500 rpm but soon as you touch the throttle, it shoots up quite a bit more.

 

To be 100 percent honest Im not sure bout the lockup type or not.. Ill have to check.. Im running the LT4 hotcam.. no other major mods were done to the motor. thats why I think I jus might have gotten too much stall to begin with.. What do u think.. Ill find out about the lockup and get back to you.

 

If the info I looked up is right on the cam, it has a duration of 218/228 at .050. 3,000 stall for your car might be just right. If you haven't already done so, put a nice trans cooler in.

 

Hey Cartman.. those specs are correct.. I just dont like the way it shifts, maybe the Detent cable needs to be readjusted.. I just found a heater core problem, so I cant really run the car just yet to get a full feel for it. Did you like the difference in shifting when u upped your stall? Am I truly doomed to get horrible mileage because of the converter now? If I were to go down in stall, whats the lowest you would recommend? Thanks for ur input..

 

I wouldnt touch anything under 2800 if i were you. And the converter has nothing to do with shifting so you might wanna check other things like tv cable or govenor. And what kind of gears do you have ?

 

runnin some 3:73s

 

Yup, I like the way my trans shifts but then again, it's a built TH400 that if bought new would be 3500+ bucks. Lucky me the friend I bought it from likes to sell things cheap. Heck I got a big block from him just for listing a few things on ebay. Anyway, the only time I had a problem with shift points was the first TH400 I had. The governor was sticking for some reason plus it had other problems like losing 1st and reverse a couple times then 3rd and reverse the last time. So, just readjust your TV cable and if that doesn't help out the shifting, check into the governor. Should take just a couple of minutes of your time to adjust the TV cable.

 

for the governor adjustment b&m sells a kit with springs and weights that might cure the late shifts. approx. $35. this won't help the high rpm at cruise speed. I agree stalls eat mileage. You could install a check ball to the tcc solenoid to get lockup in all gears but that would be silly. some valve bodys and wiring allow lockup in third gear and fourth gear and might be an alternative to high rpms if you only lockup in fourth now.

 

You will be a happy camper with a 3000 stall and 3.73 gears. Thats what i would go with.

 

Ok.. Ill give it a good run.. Thanks for your help fellas!