383 to 727 help - 66 Charger

...............1st off the flex plate is used 4 an auto trans, is bolted to the engine...the converter has the ring gear made on it for the mopars.........there is 2 different flex plate bolt patterns as well as 2 converter patterns....as well the converters are different diameters.....which do u have on ur engine and which on the converter..........prolly easier to get a flex plater to match the converter, but u can do it either way.............kim..........