I've been planning on using a factory 764 torque converter with the 727 on my 400/470. Some years back I bought a new MP SFI rated flex plate which I had not used yet so I thought I would use it finally with this engine/trans. I hadn't noticed till yesterday that the flex plate has 7/16" bolt holes and the lugs on the torque converter are 5/16". I would rather use another flex plate than invest in another torque converter so my question is, would a factory flex plate (the original from the 400 which I have) be o.k. to use with this engine/trans. combo or is the motor going to have too much power for a factory flex plate? If I shouldn't use a factory plate, does anyone make a flex plate for higher horsepower applications that has 5/16" bolt holes? The car will be street driven only as I have no plans to take the car racing at the track.