This may be a dumb question, but in switching from a 350 /350 to a 455/ same 350, which torque converter do I use? The one from the 455/400 donor car or my original? Thanks, Frank
The 350 converter should stall higher behind the big block. I assume you know nothing about the 400 converter? Kind of hard to make a suggestion without a lot more information.
The 400 converter is stock and works fine. The donor car ran when I bought it. It shifted fine... sloppy , compared to my shift kit 350, but fine. I am looking for street performance only... no 2000RPM launches or anything like that. If I take it to the track, I'll just nail it and go (if the tires can take it, which I doubt). Thanks for responding. Frank
i just did the same swap and left the 350 converter in. i didn't stall any higher. i thought it would from more torque o No:
torque shouldn't matter when it comes to stall speed. shouldn't. it could but shouldn't. I use to work in a TC shop and when someone ask for one you just ask what stall/rpm speed they want it to engage. HP and torque are never asked. They may come into play when most TC are rated like 2000-2500, more or less HP and TQ might make it kick in sooner or later in that band.
Are the 350 and 400 TC the same size and weight??? Might wanna go with the one that weighs less. Though say like in a 4 speed car. Some guys stick with stock type heavy pressure plates n parts to keep the RPMs up while they shift. Instead of using lighter race parts.
That's not what I've always been told, or read. More torque will stall a given converter higher, all else being equal. Car weight, rear gearing also affect stall speed. A converter should stall differently behind a big block as opposed to a small block. You may not be able to feel it in this case, but there should be a difference. The best that manufacturers can do is specify a stall speed range. They cannot tell you where that converter will stall in your car unless you tell them about the buildup of your engine. If you order a converter from a company like Coan, I guarantee that they will want to know every little detail about your buildup including headflow, cam, carb, transmission, rear gear, tire height, and compound, and car weight. This is so they can calculate the torque that the motor will produce, so they can build a converter that can get as close as possible to the stall speed desired. Even then the converter might need to be loosened or tightened after it has been installed and run. Engine torque matters, it's one of the most important things to consider when selecting or having a converter built.
Thats what I've always heard too, Larry. The looser the converter to begin with, the more effect torque has on "stall". This effect may be minimal on stock set-ups. Frank, what year/performance level is your 350?...What year/performance level is the 455? If you have a strong '70 350 and are putting in a '76 455...you may be diappointed.
I have a strong stock 71 350 with 72 heads and am putting in a stock 70 455 from a Lesabre that runs perfectly. Frank
Sounds like a good swap.:TU: With that engine, I would not use a TH350 tranny at all. Get The TH400 rebuilt and use it.:TU: Just my opinion.:Smarty:
