Converter stall check

[MT71c-10]

Hey guys. I want to check my stall with you guys.

71 Chevy c-10, weighs in at 3700. Edel. RPM 64cc heads, RPM cam, RPM air gap manifold, roller rockers, hyper flat top, 1 5/8" headers, 3'' collector, 2.5" dual, h-pipe, Edel 750 carb, th-350, 3:73 rear gear, 275-50-17 yokohama advan s/t tires.

It has a supposed 2800 stall, but i'm getting slow launch, Hard to do standing burnouts (without the help of some gravel or water) and when it goes from park to drive it has some rpm drop 3-400 rpm. Truck runs like an ape at 3100 rpm up, a little lazy below.

Now I know the RPM stuff works best on lighter vehicles, but I like that top end scream. The Edel carb will be replaced with a Holley vac sec 750.

The converter builder wants $175 to restall, so I want to check and see what stall I really need to run, or if a stall and regear is in order.

Thanks for the help.

[ripdog28]

Would need Cam specs to give an accurate stall. I would look at other options like tune before i tear out the trans. Never know. Just a jet change could save you a lot of time and $$. A 750 carb is a bit big for your app. I would bet that a tune would do the trick.

[gchemist]

I run a 2500 stall on a heavier truck. My ZZ4 rips the tires loose at half throttle. Mechanical secondaries are a downside to Edlebrock carbs. Have you tuned the carb with a vacuum gauge?
http://www.centuryperformance.com/tu...e-spg-148.html

For a $15 tool, you get a great diagnostic tool.

[MT71c-10]

Cam spec is 234/244 .488/.510

I have rejetted this Edel. numberous times, both with the 750 and my old 1406. I have not tuned by vaccume. Tuning is not really my strongest.

I am set on getting a Holley 3310 or equivalant. Not real impressed with the Edel. so far, I have had them on the truck for 3 years ( last 2 years with the top end makeover )

I appreciate your replys, just trying to narrow down what I can, double checking I guess.

Thanks guys.

[cableguy0]

The holley is the better performance carb hands down. Your right where you need to be on gearing. converter is close enough that it should be fine. What do you have for an ignition system? Is the timing curve set properly for your setup? Proper timing will make a huge difference in how a vehicle runs.If you hold at a stop and bring the truck up on the converter what rpm are you at? Is it actually stalling to 2800rpm? It shouldnt have an issue blowing the tires off standing on the brakes and bringing it up to rpm.

[Marv D]

I agree dumping the AFB carb in favor of a 3310 or even a 4150 will be a good performance move.
Rip, the edelbrock RPM cam he's running is 234° / 244° @ 0.050, .488 / .510 lift, ground on a 107 CL with 112° LSA

I ran pretty much that same package with a B&M 2400 shelf stock convertor and it was a SLUG off the line. Like MT71 said,, around 3000ish it would come to life and even being a hydraulic,, would still be pulling at 7000-7200. It's just NOT a low end cam. I picked up nearly 1/2 a second switching to a Midwest 4800 converter, then came a back half, and then 5.43 gears and, and, and,,,, and well we know how these things are,, a constantly evolving work in progress.
But converter and carb was the two biggest changes in motor that REALLY woke things up. After 3 or 4 months and buying the Edelbrock calibration kit, and additional rods and jets not in the kit, and fighting with the lean flat spot caused by the peepoor accelerator pump design,, I gave the stinking thing away and put a Prosystems 750 on it. WORLDS of difference in throttle response, and tunability,, and it didn't really need any tuning. I ended up one jet leaner on the secondary than just straight out of the box.

So anyways,,, I would go for the carb first. The if it isn't more responsive enough for you on the low end, throw some gear and more stall at it. You will be peeling chunks of Yohokama off the rear bedside

[bigsnookmaster]

Originally Posted by Marv D

I agree dumping the AFB carb in favor of a 3310 or even a 4150 will be a good performance move.
Rip, the edelbrock RPM cam he's running is 234° / 244° @ 0.050, .488 / .510 lift, ground on a 107 CL with 112° LSA

I ran pretty much that same package with a B&M 2400 shelf stock convertor and it was a SLUG off the line. Like MT71 said,, around 3000ish it would come to life and even being a hydraulic,, would still be pulling at 7000-7200. It's just NOT a low end cam. I picked up nearly 1/2 a second switching to a Midwest 4800 converter, then came a back half, and then 5.43 gears and, and, and,,,, and well we know how these things are,, a constantly evolving work in progress.
But converter and carb was the two biggest changes in motor that REALLY woke things up. After 3 or 4 months and buying the Edelbrock calibration kit, and additional rods and jets not in the kit, and fighting with the lean flat spot caused by the peepoor accelerator pump design,, I gave the stinking thing away and put a Prosystems 750 on it. WORLDS of difference in throttle response, and tunability,, and it didn't really need any tuning. I ended up one jet leaner on the secondary than just straight out of the box.

So anyways,,, I would go for the carb first. The if it isn't more responsive enough for you on the low end, throw some gear and more stall at it. You will be peeling chunks of Yohokama off the rear bedside

X-2 on the Prosystems carb!

[MT71c-10]

Cableguy, you are the man who turned me to the 3310 ( in a thread a while back ).

Ignition is a Mallory hei, crane blue/blue springs. Base time is 12*, with those springs I believe it is 34* total at 3200rpm ( I don't have tape or a light to tell me so ). As for bringing it up on the converter, I will try to take it out tomorrow and get an accurate rpm ( I haven't driven the truck for a few months, But roads are clear today ).

I also agree, she should be cooking tires easy.


Marv D, You are not kidding with the Edel. accelerator pump system. I have already drilled the .41 nozzle to .47 with a good response ( my numbers may not be exact at this time, but close ). I have more jets, rods and springs and all the accel. nozzles than any one needs.

I really don't want to be pulling chunks of tire off my bed, I think they look bad **s!!

Thanks for the help guys, I'm not the best tuner out there, but I'm trying. Anything helps me weed out the kinks.

[Super73]

What do you turn the motor too?

[MT71c-10]

6500 is all I have the peanuts for, thats at the "M" on the MPH. But she likes it and I'm sure she will take some more, but not with me, not right now. I'll need a lot more saftey done and a strip.

[cableguy0]

Put more timing in it. Try 16 at idle and see how it acts. Should put your total around 38. I assume your running 93 octane already? That cam will like the extra timing and you will steal some bottom end back. Also get a 1 inch 4 hole spacer and put it on. That will also help the bottom end power.

[Super73]

If it were me, I'd put a 4k rpm verter in it and let it rip

[MT71c-10]

So I got her out this week for a little drive, man it felt great, except for all the gravel getting thrown up.

So after it got warmed up held the brakes and hit it, it feels like the converter loads up around 2000-2200.

[cableguy0]

Do you have a tach? or are you guessing? A couple hundred rpm will be night and day in stall speed. If you just stand on the throttle without the brakes what rpm does it flash to? It really sounds like you need a higher stall converter. The things i mentioned will help a bit but if your putting that engine under load before its making any power its gonna be a dog.

[MT71c-10]

I do have an aftermarket tach. Just standing on gas from a stop I would guess in that same rpm area.

I do also think I got a little taken by converter builder.

[cableguy0]

Your stall is way to low. its definately going to be a dog. a true 2500stall in a heavy truck with some power should flash to around 2700 when you just stand on the throttle. generally you will get a range for example 24-2600 would be considered a 2500 stall 28-3200 would be a 3k stall. You get what you pay for when it comes to converters. I would personally use tci,bte boss hogg etc. I dont like the B&M junk.Theres a bunch of companies I didnt name just because i personally havent used them. Get you a 3k stall and that thing will seem like a rocket.Did you advance the timing a bit?

[MT71c-10]

Yea advanced untill I started hearing a ping then backed it up a tad. Converter guy is out of Idaho, I'm still trying to dig up the info on them.

[MT71c-10]

All my receipt says is 9.5" high stall GM torque converter $369.00

Was purchased through a reputable tranny shop here in town. I'll go in tomorrow and find a little more out.

[cableguy0]

They really f'd up if a 9.5 inch converter is only foot braking to 2200rpm. Normally would use a 10 inch converter in that stall range. That cam is going to like as much timing as you can give it. What fuel are you running?

[MT71c-10]

I'm pretty sure all we can get here is 91, that's what I run. I'm pretty sure they run some ethanol in the blend here in the winter, but the same problems exist in summer. I would think aluminum heads would give a little room to play.

I'm going to pull the timing cover off here soon and triple check my timing, TDC, and put on a new timing chain set.

I'm also a little confused about the converter, I thought they told me it was a 10", but when I ordered it I gave them all the info, cam card, weight, gearing, etc. I wouldn't think any one would build a converter in a 9.5" with that low of a stall either, I would think it would just be a loosened up stocker.

It's $175 to restall through them. I don't know if i can trust them. Will other converter company's touch other manufacturers product?

Is there something in my trans that would cause this to happen? I wouldn't think so, It would just be slipping if it were on it's way out right.

When I changed the converters, oil and filter looked and smelled clean.

[cableguy0]

No its definately a converter issue. Your exactly right the transmission is either going to engage when the converter "locks up". Nobody else is going to touch that converter. You can get a boss hogg unit for around 400 bucks that will have torrington bearings and an anti balooning plate which should be in any converter in a heavy truck with high hp.Anti balooning plates are listed as a neccessary item for nitrous but getting a heavy vehicle moving stresses the converter the same way so its just some insurance.I personally wouldnt trust them at this point. If they didnt deliver what they were supposed to the first time whats to say it will be right the 2nd time. Im sure they will give you the bs line about theres always some variance in converters and we cant exactly guarantee stall blah blah blah..... so i doubt they will do anything without you paying for it. Generally a 2200 stall is an 11 or 12 inch converter as you said. 11 inch will go to around 2500 stall.

[MT71c-10]

POOP! I'm going to call the tranny shop and get the name of this place, and ask a few questions.

Thanks for all your help cableguy, much appreciated.

[cableguy0]

Places on ebay are selling the boss hogg stuff for like 300 bucks and summit has the tci stuff.

[cableguy0]

Have any luck with the converter builder?

[MT71c-10]

Its a place called Hi Torque out of Idaho.

Ran into a guy that works at the tranny shop I got it from and said "they would try and see what they can do for me". This guy does know my truck and may be able to help pull some strings. I'm not counting any chickens here though.

I have to try this route right now beacuse me and the Mrs., wedding is almost a month away and can't spent any for a new converter right now.

Have to buy them friggen flowers right!

I will keep you updated.........