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Torque converter info

mrk5

mrk5

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My new engine for the C10 recommends a 2200-2500 stall. I've not messed around much with converters.

Are there downsides to a higher stall converter?

Would a converter like recommended cause issues if I tow a 4500lbs camper?

Some of the converters I've looked at in that range say it's based on a big block and a small block would be 300-500 RPM lower. Should I look for a 2500-2800 stall?

Any other thoughts?
 
mrk5 said:
My new engine for the C10 recommends a 2200-2500 stall. I've not messed around much with converters.

Are there downsides to a higher stall converter?

Would a converter like recommended cause issues if I tow a 4500lbs camper?

Some of the converters I've looked at in that range say it's based on a big block and a small block would be 300-500 RPM lower. Should I look for a 2500-2800 stall?

Any other thoughts?
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I’m no converter expert, but I do know I put a converter like that in my obs and it overheated the trans pulling my boat. @Greg Ducato ? @Bent77
 
I’d be concerned about not getting off the converter at cruise speed.

Other than what they’re recommending, what are you hoping to accomplish with more slip?
 
Stall speed depends on multiple factors cam choice is one. So an advertised stall speed at 2200 may actually be more or less depending on the cam.

I’m with Mark on this one. I’d be worried it won’t be off the converter at cruise speed.

It’s not a drag truck. You don’t need to have a loose converter. If you do plan on some light towing I’d stay closer to stock stall speed. Yeah you give up a little performance but you’ll save the trans from cooking itself and the truck won’t feel soggy until it hits that higher stall speed.
 
2200 + = race car.
At 2500 you probably wouldn't get a good lock at cruise.
 
I was worried it might cause more trouble than it's worth. I've never had a torque converter that wasn't just a factory stall.

Mostly I was considering the converter change because I wanted to experience the full benefit of the new engine. But I also don't want to destroy the drivability.
 
mrk5 said:
I was worried it might cause more trouble than it's worth. I've never had a torque converter that wasn't just a factory stall.

Mostly I was considering the converter change because I wanted to experience the full benefit of the new engine. But I also don't want to destroy the drivability.
Click to expand...
Greg will be along and give you his question list. He’ll set you up good
 
I’ve been talking to circle d about my 4l80e converter with my 383 I’m putting in and we are looking at a 2100-2300 stall on it. I spend more time on the street than rocks so I want the little better performance plus with the high first gear in the 4l80 that’ll help offset some of that. Trans gear ratios, axle ratios, tire size, cam, heads, everything affects stall speed. Converter stall is an art and I’ve known folks that will go through multiple revisions to get one that works. I also know people that daily drive a 4500 stall so there’s that to.
 
I have a theory that "engine recommended" stall speeds are really "engine in a light car recommended" stall speeds and a truck will need a step or two lower. I personally hate high stall for towing. Had 2000 RPM in my K5 for a bit (stock 350) and swapped back to stock. Best thing I did to my 4L80E Suburban was switch from the loosey goosey 6.0L converter to the nice feeling 8.1L converter. (Scratch that, 2nd best thing, the actual 8.1L swap being the best.) Especially with a mechanical fan, I hated the roaring of the engine to take off gently.

If you're building for mud or sand drags, that's another thing.
 
years ago i had a built 400 sbc in my k10 on 1tons and th350 with 4.10 gears and 38" tires . my trans guy that did the th350 put in a allison at545 converter for more truck use and i can say it was different and worked great . and that 400 sbc would hit 6k no problem as it was balanced / polished / de-bured / knife edged crank ......... she was a animal . i miss that engine :frown

same guy that built the trans had a stock 454 with edelbrock top end and same built th350 in a short bed on 1tons and 4.56 tires . close to same trucks and he was blown away how hard it launched and pulled his 454 truck .

i do agree with there recommend specs are for light stuff .
 
I like a firm shift from my automatic transmission. I would think that you could do a Transgo shift kit easily without doing anything more than dropping the valve body. I honestly can't remember from the last TH350 that I did.
@Greg Ducato did a nice job with my converter for my 6.0 truck, even though it feels somewhat odd compared to all of the stock ones that I have had. It pulls at idle, but lets the engine come up in rpm to get the truck rolling.
 
Greg Ducato said:
What transmission are you using? What is the camshaft part number or camshaft specs? How often do you tow and what kind of weight?
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It's a TH350. Cam specs: 220/224 @050 .495in/.502ex 110LSA. The camper weighs 4500lbs. The truck is a regular cab, long bed C10 that probably weighs around 5000lbs. FWIW, here's the dyno graph for the engine.

HP98-3.jpg
 
I assume this is a small block? That will be a pretty choppy cam at idle in a 350 and vacuum won't be the best but it's certainly livable with concessions. You will need at least a 2500 stall to get a half decent idle in gear at about 850-900 RPM. That would not be my choice for a towing application, a higher stall converter builds more heat. It will be a lot of fun to bomb around in unladen!
 
The TH350C has a lock up converter. I thought that it was only available in 1981 and part of 1982, however I am not positive.
 
I don't think I have ever seen 1. I was a gm tech not long after they were offered. Saw a ton of 200-4r
 
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