I like stirring the stick, so I'd keep the manual, especially, since it is already set up for it. But, that three speed is weak in the first-second gear, and does not like shock loading - like dumping the clutch in second, or speed/power shifting from first to second, and sidestepping the clutch. Even a stock motor will break second gear if you treat it that way. I broke two of them in my '51 with the worn out stocker; then after I rebuilt it and warmed it up considerably, I started collecting the trannys, so I could have a spare, and a ready parts source. I suppose if I'd kept the car, I might have sought a solution sooner or later, but I went off to see the world with Uncle, and my Dad dumped the car. You could get an adapter and put a later model four or five speed in it, but then, unless you're just real fond of shifting, you might as well do the C4 conversion.