Choosing the Correct Style/Size Torque Converter

[Duts87ss]

I need some help finding the right converter for my car. I'll allow the company that I choose to help me get the correct stall speed, but what I need to know is what size converter I need (modified D5, 11", 10", 9", 9x11).

Info on the car:
'87 Monte SS
383 sbc being built - 425-450hp, 450-500ftlb (estimates based on a desktop dyno type program someone ran for me) (peak power and torque happen before 5000rpm)
3.73 gears (the 7.5 is going to be addressed) (thinking of switching to 3.23 or 3.42 to keep the highway revs down some)
BowtieOverdrives Level 2 200-4R

This is not a track car. I've never had it to the drag strip to date, but will probably go a few times with the new engine to see what it will run. I may also take it to an autocross a few times, but for the most part it will be 100% street car. I like to have fun driving my car like anyone else, but the main concern is streetability.

I'm currently running a BTO 2200 stall converter that I really dont like at all. the engine has to rev to 2000 rpm before the car even wants to move. I liked the way the factory D5 acted with the stock 305 and even my current Goodwrench 350, but am not sure if it will be the best choice for my new 383.

I appreciate any advice given. Thanks,
Dustin

 

[mikestertwo]

What cam are you running?

 

[challengermike]

Sounds like you converter has problems.A 12" converter should drive normal on the street and not reach its full stall speed untill you mash the throttle.Even a good 10" or 9" will be pretty much normal with only alittle more slip on light throttle.As for the right stall speed you want to match it with the cam in the car.If the cam starts at 3,200 rpm you want a converter right around that stall speed.That way there wont be any waiting around for the rpm where the car starts to pull hard(power band).With a stroker motor you will usually get a converter with alittle less stall to stall alittle higher due to more torque.

 

[bison]

What cam are you running?

x2 and what is the weight of the car? If a small hydraulic you can go with less stall. If a solid you will need a looser converter

 

[Dusty Bradford]

You looking for lock-up?

 

[Duts87ss]

Thanks for the quick replies guys. Didn't even think about mentioning the cam specs.

Cam: 268XFI hyd. roller
Gross Lift: .570 int, .565 exh
Adv. Duration: 268 int, 276 exh
Valve timing: Open: 25 BTDC int, 75 BBDC exh
Close: 63 ABDC int, 21 ATDC exh
installed at 109
Duration @ .050: 218 int, 224 exh
Lobe Lift: .357 int, .354 exh
Lobe Separation: 113

Comp lists the rpm range at 1800-5800. I figure it will be a little less with the extra cubes. Heads are AFR 180 Eliminators. Using a ported TPI intake.

Dusty, I'm definately looking for a lock-up converter.

 

[Duts87ss]

Weight of car with driver is ~3800#

 

[fastdon3]

converter company will ask you every thing get your pen and paper ready they need to know every thing from weight of the car to combination of engine trans and rear end

 

[Dusty Bradford]

Probably need a 2800 10" Lock-up but you need to pin down the rear gear ratio before deciding on the converter. 3.23 is a long way from 3.73.

 

[John Wilde]

Dustin,

Go with Dustin...
Bradford knows is stuff.

 

[Duts87ss]

Dusty, I think I've decided on going with 3.42s. I'll also try to find a dyno graph of an engine similar to what I'm having built.

 

[Dusty Bradford]

OK. I sent you a PM.

 

[Duts87ss]

Here is a dyno chart of an engine similar to mine. It's a 355 instead of a 383 with almost identical specs other than displacement; I would think this would make the curves move up and to the right a bit. This was on a chassis dyno.