Stall Converters

[1980Bu2Dr]

Hey Guys,

I've been considering trying a Stall converter on my Malibu and just looking for some info. I'm thinking it will help wake up my Bu off the line a little since its a little sluggish due to the rear gears and cam.

Here's some info on the car:

2 dr Malibu
305 with stock heads and stock bottom end
Comp Cams 268h cam
Cam Specs -
Operating Range: 1500-5500 RPM
Duration Advertised: 268° Intake / 268° Exhaust
Duration @ .050'' Lift: 218° Intake / 218° Exhaust
Valve Lift w/1.5 Rockers: .454'' Intake / .454'' Exhaust
Lobe Separation Angle: 110°
Edelbrock Performer Intake
Hooker Comp full length headers
TH350 transmission

I'm not sure on the rear gears cause I haven't pulled the dif cover yet. It runs about 1900-2000 RPM at 60 mph. I was thinking of trying a 2000 stall because once i hit 2000 RPM the car screams. Question is will this affect highway driving. I've also noticed the motor likes to get a little warmer when the car is in gear and stopped at drive thru's due to the low rpms so i'm constantly shifting in and out of gear. Will the stall converter help this as well. I found a used B&M 2200 stall nearby for $175 and am thinking of giving it a shot. What do you guys think?

 

[DRIVEN]

The 2200 will be fine. Remember that a torque converter's stall speed is relative to power output. Your 305 will have a lower stall speed than a 502 using the same converter. Honestly, the bigger thing holding you back is probably your rear gearing. Given your stated speed/rpm, I'd guess you have 2.41s or something close to it.
Your overheating issue is not likely transmission or converter related. If you still have the stock fan setup you may have a failed fan clutch. I assume the shroud is still intact?

 

[olds307 and 403]

The converter will definitely help launch. You need a new fan clutch to help low speed air movement. Make sure your fan shroud is intact and undamaged too. The only thing a high stall converter is supposed to do is increase full throttle launch rpm. A good one slips very little down low at light throttle and up top cruising. You could add a good sized trans cooler, if your worried. Sounds like you have low 2 something gearing, great for long trips.

 

[olds307 and 403]

Driven beat me to it 😀. The 2.41 was a very common gear for 80, only option on the Delta 88 that year, maybe others too.

 

[DRIVEN]

Clairvoyance :wink:

 

[1980Bu2Dr]

Honestly now that i think about it the warm temps at low rpms are likely due to the plastic fan i'm running....and i don't have a clutch. Probably just not moving enough air. The shroud is intact. It had a small hole that was fixed wonderfully with duct tape. Maybe i'll put the other fan back on and see what it does. As for the rear gears. I like the fuel mileage i get...just looking for a little more launch. I was more worried about whether i'd build to much heat with a higher stall while cruising at lower rpms. Maybe i'll give it a go, its only money and i'm making more right now while typing this....

 

[Intragration]

Depending on what kind of driving you're doing, you might not hurt your mileage all that much with a higher numerical rear gear. Lugging from a stop with 2.41s takes a lot more effort than a nice easy start with say 3.42s. If you do a lot of highway driving, you may see slightly reduced mileage, but it shouldn't be drastic. I think I went from around 15 mpg to around 13 mpg when I switched from 2.41s to 3.42s, that's with a 455. It was a night and day difference though in terms of performance. Even with a high-stall converter, you're still fighting an uphill battle with 2.41s. You can check your gear ratio without taking the cover off, just raise the rear end and with the transmission in neutral, spin the driveshaft and see how many revolutions it takes to make your rear tires go around once. An open rear, only one tire should spin, and it will spin twice as fast as normal.

My suggestion would be to definitely get your cooling situation in order before anything else though. What does it get to idling versus cruising?

 

[1980Bu2Dr]

Right now at cruise it runs at 185....if at idle and in gear it climbs to about 195 or so (that's the highest I've seen it before i dropped it into neutral). If i put it in neutral it will drop back down to 190. It probably is because i put the lightweight plastic fan i have on the motor instead of the stock one when i swapped motors. I'll throw the stock one back on and see what it does.

 

[Intragration]

That should help, although even 195 isn't bad. What's your thermostat rated for?

 

[84GP455]

I added an electric fan along with the clutch fan, and a transmission cooler with a 160 thermostat and that cured any overheating problem I was having. As far as the converter goes, I added a 1800-2000 stall back in the day to my TH400 with 2:41's and it did make a difference off the line.