Only the 1973 340 was externally balanced as far as the LA engines go. All the rest were internal. Also, there are plenty of converters well below 1800 stall speed, such as trucks. I've seen as low as 1100. So I don't know where "that" came from.
A lockup converter is for a later model transmission designed to
Huh??? All 360's are external balance. Are you feeling ok RRR? Harmonic balancer and Weight on torque converter. You probably don't have a lockup type transmission.
speed. The benefit of this is, it acts like another gear and lowers engine RPM for greater mileage on the highway through reduced engine RPM. Unless you have a lockup transmission, leave the lockup converter alone. It will not work with a standard non lockup transmission, such as the regular three speed 904.
Also, yes, there are plenty of converters under your