Submitted by Cory on 10/12/03
If the converter is for a 727 and has no weights it should work, unless you have a '66 transmission, which has the smaller input splines. There were a handful of cast-crank 383's made before the 400 came out, that would explain the weights on your converter. I actually saw a '69 383 with a cast crank and it looked like an original, unmolested motor. The 318 converter the other guy has, if it's smaller than the 12", will give you a higher stall speed and probably much better performance that the 12" one you bought at the trans shop. Small cams and big converters are good for towing but not when your HP/weight ratio is higher. Another thing to keep in mind is that there are two diameters of flex plate, make sure the plate matches the converter before installing the transmission.
To answer your questions, sure, you can use a used converter, but not if it has junk in it or if the fluid in it smells burned. Yes, you probably were sold a correct converter for a plain-old standard, non-externally balanced motor. You can do better.