10.5" to 11" Clutch???

My brother has a 68 super bee with a 400 big block 484 purple shaft cam,750 edelbrock carb,edelbrock performer, rpm intake,etc and is going to a 4 speed trans so I called Brewers performance and asked for a 10 1/2 " flywheel and a 11 " Scalloped Clutch and I was yold that clutch was alot more than needed. He also said it was good enough for @ 600 horses or so. By the way we did get the diaphram style pressure plate all from McCloud.I would suggest calling either brewers perfomance or the clutch manufacturer for their suggestions as per motor size ,bell housing size,rear end gear ,and tire size. Call around and see what is said from different companies and compare to see if any agree on application!! Good luck