Torque Converter question?

[ChevyGearHeads]

I have a stock LM1 with double hump heads, .500/.500 Cam
and a Hurricane intake with a 600 CFM Edelbrock carb.

With the Hurricanes 3,000-8,000 RPM Power Range, I was wondering what the best stall option is for a TH350 with a current 1,700-2,100 Stall?

[garyd1961]

I'm not an expert on stall converters but since no one else has answered I will give it a shot. To start with you need to match the converter to you cam not the Intake. My best guess is with a 500 lift cam you will need about a 2200-2400 stall.
The weight of the vehicle and gear ratio in the rear has a lot to do with it also. A heavy vehicle can make a 2400 stall operate more like a 3000 stall. The more stall you have th he bigger gear you need in the rear. I can tell you from experience a 3600 stall will not work with a 308 gear in these trucks.
So here is my thoughts on this, the bigger the cam the more stall you need. The more stall you have the bigger the gear you need in the rear. Not having anymore info than you provided and with my limited knowledge on the subject I wouldn't suggest you go more than 2400 stall.

[Tom]

He's on the money. We need duration specs @.050 more then anything.

[mongocanfly]

Or call the converter manufacturer, give them the info they need , they'll tell you what you need...
But also agree with all above...you need your full cam specs...along with alot more info on the truck..

I used to run a vega convertor ( approx 2200 stall) behind a flat top 350 with 500/300 cam...worked good with 5.13 gears and t350

[Ziegelsteinfaust]

You'll want atleast a 2500 rpm stall to allow the engine to idle better.

We need gear ratio, and desired tire height too. These can crutch a engine with low torque, and move relatively ideal around the map. Also the cam duration is a big deal. More over lap the lower the torque, and bigger need for a high stall converter. Judging by the rpm band your in the neighborhood of 250 duration at 50 thousandths. Or roughly a duntov 3030 cam.

A deep gear ratio like 5.13's are less stall sensitive then lets say 2.73's.

2.73's will get more cowbell from a loose converter the. 5.13's.

Converters are fuzzy logic, and simple changes can have big effects.

[garyd1961]

Originally Posted by Ziegelsteinfaust

You'll want atleast a 2500 rpm stall to allow the engine to idle better.

We need gear ratio, and desired tire height too. These can crutch a engine with low torque, and move relatively ideal around the map. Also the cam duration is a big deal. More over lap the lower the torque, and bigger need for a high stall converter. Judging by the rpm band your in the neighborhood of 250 duration at 50 thousandths. Or roughly a duntov 3030 cam.

A deep gear ratio like 5.13's are less stall sensitive then lets say 2.73's.

2.73's will get more cowbell from a loose converter the. 5.13's.

Converters are fuzzy logic, and simple changes can have big effects.

The power range he quoted was for the intake not the cam.

[ChevyGearHeads]

Thank you guys! The Cam RPM range is 3,400-7,000 and I'm currently running 235/70R15 which will be replaced with something bigger eventually.
It should have the stock 3.73 rear.

[garyd1961]

Originally Posted by ChevyGearHeads

Thank you guys! The Cam RPM range is 3,400-7,000 and I'm currently running 235/70R15 which will be replaced with something bigger eventually.
It should have the stock 3.73 rear.

Did the truck come from the factory with an automatic or manual transmission?

[Ziegelsteinfaust]

That cam is a bit extreme for 3.73's as the torque won't be there to move off the line nicely.

Let's figure your going to run 28" tires which will be roughly a 275-60-15 of a 7-8 inch rim. Since the tire size you listed would change to match the trucks whole concept now. I would seriously consider going big to 4.56 gears to allow the engine to be in its power band at 70mph, but also allow mechanical advantage for lack of torque off the line.

Your current combo of tire, and 3.73's puts you at 3100 rpm at 70 roughly which is below the cams stated power curve. Personally I would prefer to be right at the bottom edge of the power curve for better mpg or manners at speed. Factor in the manifold you have you need to keep air speed up for the carb, and engine to be happy. My friend ran a Duntov 3030 with 4.11's, and at 70 it would slow down going up hills due to lack of torque. Where as my torquey 350 didn't care about hills since I had tons of torque by comparison. Yes large hills like the cajon pass needed more throttle, but small ones didnt seem to make a difference to my 70 mph only cruise control system.

Lastly I would seriously go for a 3000-3500 rpm stall with the 4.56 gears to bring your combo into a happier zone. Plus invest in foam ear plugs, and then enjoy

[68c10owner]

Originally Posted by ChevyGearHeads

Thank you guys! The Cam RPM range is 3,400-7,000 and I'm currently running 235/70R15 which will be replaced with something bigger eventually.
It should have the stock 3.73 rear.

Can you post the entire cam specs so we dont have guys guessing at what cam you got? Lift and RPM range isnt all we need. Take a pic of the cam card and post it.