Thermoquads

hey guys thanks for the advice....pettyblu, i thought that carb was mechanical secondaries? isnt 750cfm kinda big for a 340 like mine? Also i know thermoquads came into sizes...which would be more ideal for me? and has anybody ever used the holley reman thermoquads? they are a great price and look like a nice peice in the picture, but id be interested to hear anyone's actual experiences with them