I have a 455 10:1 CR, Ported cast heads,Crane cam H218, 2.93:1 gears and car weights about 4400 lbs (no headers). Now I'm looking for a new convertor for my TH400 and I've seen one with a stall speed of 2000-2500 rpm. Is this a correct convertor for my car and if not, what kind of stall speed do I need? Thanks, Bram
Bram, I don't know what a Crane H218 cam is. Can you provide the specs? That would sure help. I'm guessing that it might be a mild cam if the 218 means 218* duration. In that case, I would choose at most, a 2000 RPM stall converter. You don't want the motor below stall speed on the highway, and considering the 2.93 gears, that's a real possibility if you select a converter with too high a stall. In reality, no one can tell you exactly where the converter will stall, unless you contact a converter manufacturer, and give them all the particulars of your engine, and car. If you buy a converter out of a catalog, you'll see a stall speed range. Car weight, and engine torque have an effect on stall. Any converter will stall higher in a heavier car, and stall lower in a lighter car. That same converter will stall higher behind a big block than it does behind a small block, because of the engine torque. If you have the power range of the cam, you want the cam to stall about 500 RPM above the lower number. This chart from the Summit Race catalog helps.
Larry, You are right about the cam specs. Cam timing @ .050": Intake opens 2 # BTDC Intake closes 36 # ABDC Exhaust opens 50 # BBDC Exhaust closes 4 # BTDC The intake has a duration of 218 # and the exhaust has a duration of 226 # @ .050" The power range of this cam is 2000-4500 rpm, so as out of your story I have to choose one that stalls about 2500 rpm, so can I say that the convertor I have seen should be fine Do No . http://www.cranecams.com/index.php?show=browseParts&action=partSpec&partNumber=850571&lvl=2&prt=5 Have you got any idea what the stall speed is of a stock convertor? Thanks for your help, Bram
Bram, Stock converters usually stall around 1400-1600 RPM. Yes you can use that converter with the Crane cam. When you are on the highway with a 2.93 gear, at 60 MPH what will your RPM be? If it is below the stall speed of the converter, it will slip a little more, and make extra heat. It shouldn't be too much of a problem, make sure you use a auxiliary cooler.
