Hello Fellow Hambers, Looking for recommendations for torque converter stall speed for C4 behind a stock 1950 Mercury flathead. I noticed the Speedway kit comes with a 2400-2600 rpm stall torque converter. Any feedback is greatly appreciated. Thanks.
It depends on how you intend to drive the car. The stall speed also depends on how much torque the engine makes. I don't like high stall convertors for a street driven car. A stock 50 Merc flathead develops peak torque at 2000 rpm. I would think a convertor with an 1800-2000 rpm stall would be ideal for a street driven car.
What you need is a stock C-4 replacement converter for what your doing no need to think about stall speed. Any good transmission shop should be able to get you a rebuilt stock converter but you need to know what converter fits the C-4. The input shaft spline count is different between early or late transmissions and also what flywheel mounting pattern is on the flywheel to mount the converter. Once you know this information a replacement converter for a given year and application can be determined. Overall you would be looking at a small block powered Mustang with a two barrel and even one with six cylinder the converter mounting bolt pattern for these application's may vary but the pattern used on your flywheel is what would determine the stock application in the end. I have built many C-4 flathead conversions the stock converter has always been a perfect choice. Including the one in my wife's blown flathead in her Deuce coupe. Ronnieroadster
What engine closely matches your flatty in HP and torque production and RPM? Most likely a 6 cylinder converter will work best.
Had a stock 69 Pontiac 400 HO engine, the turbo 400 went south. The rebuilder talked me into a 2500 stall converter. What a disappointment, street driven car, draws attention leaving the stoplight. I gave it chance, but after a month, had him order a stock unit. I vote for a stock converter.
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