keen 4" flares sluice box is 48" long and 16" width I don't know how high the sides are but if I can remember they were 4" to 6" high and I think 6" wood be better if you plan on using two P180 pumps the 4" dredges come with a P180 at 300 GPM or a P280 at 340 GPM pump and a some of the 5" dredge use two P180 pumps there flares sluice box is 60" long and 20" width and I think about 8" high so if you going to use the two P180 pumps I wood make your box 20" wide and 7" to 8" high

Thanks Jeff, I was leaning towards the dimensions of the keene 5 inch box and I've had a few other people that I've talked to make the same suggestion. And you know they say, "when you have several people telling you pretty much the same thing, you had better listen".