Syco79

Well im a complete newbie and im about ready to order This engine from T&L. Ive been told that I should upgrade my stall speed torque converter. I did a quick search on jegs and there 2 full pages of matches for a 79 corvette . The engine has about 450 hp 530 torque and I have the stock th350 auto transmission. Can someone please point me in the right direction. Thanks!

kevinator80

Without getting real technical, I would suggest a torque converter with a stall in the same neighborhood that your engine begins making good torque and this will depend on the cam you choose. For instance, if the cam says its powerband is 1800 to 6000 rpm, go with a 2200 to 2400 stall converter. But hey thats just me. Get these tech gooroos some detailed info and they can help you much better than I can. They will want: cam info, rear diff. ratio, street/strip/daily driver, OD or not.

enkeivette

Damn that's a lot of power, might as well order a better trans while you've got your check book out.

Syco79

Well I guess I should wait for the dyno results then to order one. My dif ratio is stock I believe 3.08 but hey whats wrong with the stock th350? Ive been told its a good tranny atleast I hope it is cause after the engine im broke

kevinator80

The 350 refers to the torque its rated to handle. Your new engine is slightly above that.

Syco79

hmm the new engine is way above 350. I guess I need to plan on upgrading or getting a new tranny at the same time now hu? I never planned on that might have to hold the project for another month or two if thats the case

kevinator80

Don't forget the rear differential has its limitations too.

JPhil

Car Craft Magazine had a real good article about torque converters and stall speed ,well, over a year ago. Check their website and look in tech articles."What's Up With Stall" I believe it was called ...Also, look in Jegs and Summit catalogs for brand names, then make some phone calls to the companies. Have your car info handy--weight, gears, cam, type of use, etc. It really is a component which needs to be matched to your individual car if you want to be happy with it.

John

Syco79

Oh my poor dreams are shattered . Looks like my entire theory of buy a engine pop it in and go just got blown to bits I better sit down with my mechanic and figure out what "else" needs to be done.

SIXFOOTER

check out Bowtie Overdrives, they have a whole lot of info on this

ratflinger

No, no, no! There is nothing wrong with your Turbo350 & don't get convinced otherwise. A T350 can easily be built to handle that torque & hp. If you do the de-install & re-install, then a good shop will rebuild the T350 for this power level for about $500. You may want to consider 3.55 or 3.73 diff gears, but a good stock diff will easily handle this hp & torque.

Now with that said, the tranny change will depend upon your planned driving habits. If this will be a daily driver then an OD tranny will make up for it's price differential with gasoline savings. If you are just building a weekend crusier, then you'll probably never achieve the financial savings, but might still want the lower RPMs for cruising. I'm sticking with my T350.

As far as the converter goes, 2500 - 3000.

lebvette

2500 give or take a hundred. Larry

The Money Pit

I'm in the process of re doing the tranny in my 80 for the fourth time in as many years.When looking at a converter I found most venders will advertise the stall based on something like 230 lbs of torque.This is misleading info for guys that run high powered engines.A big block will make a 2500 rpm stall act like it's a 3000 rpm stall,if you see what I mean.
Another thing I discovered is the torque ratings are seldom mentioned.I was almost ready to order an ATI 10" StreetMaster converter,and spoke with their tech department prior to placing the order. He told me the StreetMaster would not handle the power I was making,and recommended a TreeMaster which cost $200 more,but would hold up to the power levels.I called Transmission Specialties and spoke with the tech there,and he also recommended a XHD version of their 10" converter.It's rated for 850 hp and has anti balloon plates(for nitrous).
The point being,not only is the stall speed a concideraton,but the strength of the converter must also be taken into concideration,or the converter will fail.This in turn will cost you a transmission,and worse yet........more down time for the Vette.

Ask me how I know this.................

kevinator80

He never mentioned doing a thing to the rest of the driveline, therefore I warned him of his stock equipment limitations. $$ can fix anything.

Syco79

Thanks for all the info guys I was really worried about this. It turns out my Uncle's neighbor owns a transmission shop so im going to go over and talk to him about having my th350 beefed up maybe my mechanic can pull it when he pulls the engine and it wont cost me all that much. I just had my stock diff rebuilt to stock specs last year so hopefully it can hold up to the power heh. Im guessing this is still going to delay my project at least one pay check but its my money pitt and itll be worth it.

Matt 1980 L-82

I've seen it posted several times that a stock diff will be fine as long as you use street tires and not slicks.

73'454folendore

Sorry, must disagree about the th350. He just spent a lot of money on this engine. Why spend $500 to have the Th350 upgraded when you can pick up a used/rebuilt TH400 for the same price. The Th350 will hold up but will not have the reliability of the TH400. I agree with the 2500-3000 converter, just on a TH400. I think with that HP he will be pulling that tranny out and replacing or repairing soon. Measure twice cut once. My .01 cent.

Buffalo Dude

For OD, you'll need to drive in the neighborhood of 70k+ miles to regain the initial cost in gas savings. For sustained highway driving, you may see less wear and tear on other parts, but OD should be more about drivability than cost savings.

I have a 2200 rpm tc right now that I'm pretty happy with, but I'm running the stock L48 and a 200-4r.

69camfrk

Check out a company in Abilene, Texas called Torco. They will build you a killer converter at a great price. Tell them what you have and what intentions you have with the car and they will make a good recommendation. Racers in that part of the country will tell you the same thing.

69camfrk

I may have given you bad information. I tried to find the Torco web page and it appears they have been bought out by Art Carr. Hopefully they still have the same good prices and great converters. When I got mine two years ago they were still Torco.