383 harmonic damper

I am building a 383 for my dutser, it has a cast crank and is externally balanced. I want a quality damper i was going to use a fluidamdr but they only make a internal balance model. also will i need a specialy balanced flex plate to run a 2500 internal balanced stall converter. I had to get one for my 360 but dont know if its required for my 383. any input would be gret thanks.