Here is what I have
383 11.5 to 1 forged
LE AFR 195's to about 217 w beehives
LE ported LT4 manifold
cc306 (yeah not the best decision)
Holley 58mm throttle body
7/16 studs with promag 1.6 rockers
meziere pump
SFI damper
AS&M mids
comp 850 lifters
Other stuff as well,but that is an idea of revability

Going to get a new 700R4 soon so i can get this thing running.Car has 3.23,s that will probably get yanked for 3.73,s.What I need is a converter suggestion for stall speed as well as a STR suggestion.Where should the shift points be to take full advantage of the combination.This is going to be weekend car with 75% street and 25% track use. Thanks

 

Sounds like you've already decided on a 700R4, but FWIW a 4L60E can be built just as strong. As far as a converter, forget "stall torque ratio" as there is no way you can compare one manufacturer's ratings with another. And even if you could, you don't know enough yet about how the car will behave to decide if you need more or less. In any case, as far as I am concerned, more is better unless you are very traction limited. Which brings up the question of what tires you will be using. A converter optimized for the strip will have a stall speed a 500-700rpm lower than peak power. This can be very annoying on the street. At the track IF you are runnning street tires, it may be very hard to launch the car without smoking them with a converter with that high a stall speed.

A CC306 would need something in the mid 4,000rpm range, and like I said, that will be less than fun on the street and may not actually work best at the track (due to traction issues) even though it would be theoretically optimal. So, your choice is going to be very much a compromise. In the end, a stall of about 3,500 may well be what is the best balance between street and track. You need to decide how much you are willing to put with on the street as well as taking tires into account. I suggest you think about this for a bit and then call a good converter manfacturer (Coan is my favorite). Most of the time, you will end up sending it back at least once for adjustment and you will only be able to do this with a high quality converter bought directly from the manufacturer. I also like ATI.

Be prepared to spend a few bucks on a good converter. If you go for a stall in the 4,500 range, for a non-lock up race quality you will be in the $7-800 range, a couple of hundred more if it's a lock up tranny. If you go for the lower stall speed (3,500 range) you will get away for a couple of hundred less.

Here's my Socratic question for the day: why are high stall converters more expensive than converters with a lower stall speed?

Rich

 

This is a 93z by the way

 

Because the quality of the "guts" are higher and obviously cost more. More labor intensive too. Although I dont understand the HUGE gap from say $200 for a converter to $800. That seems a little crazy.

Anyways,......yeah,..... what he said in the rest of his post. Gotta figure out what you're willing to put up with while driving this thing on the street. And how much gas you wanna waste. I chose a stall slightly lower than what it optimally needed just because the driveability is better and the street is most of what the car sees anyways. Dont forget, with a super high stall you're going to need a nice trans cooler setup to take care of the additional heat. Also, if you're traction handicapped, like rich stated,......you dont want a big stall to match the engines TQ peak or you'll just burn tires all day long. Instead go lower and you'll actually end up faster because you'll get out of the hole quicker with no wheel spin then pull like crazy once you get movin'. Good luck.

 

Right! If you think about from the point of view that, in general, a higher stall converter is physically smaller, it even makes it more apparent that to handle the hp, stronger (and more expensive) parts are needed. Imagine the pressure and heat generated in a high stall converter used with a transbrake when the brake is applied and the motor is at (or near) peak power.

Good point about the cooler, though you are going to need one either way - with a 3,500 or a 4,500 stall as in this example. However, as you point out, the higher stall will generate a (lot) more heat. This potentially decreases tranny life. I agree that unless it's a race car ocassionally driven on the street the best bet is not a converter with an extremely high stall speeed.

Rich