[bigeasy1]

Try part # SEA071391 by Seafarer marine products.They are all polished stainless,and were a direct replacement for the vents on my 1974 Tsunami.
They measure 12-3/16" long by 4-3/8" wide on the outside,and require a cutout hole of 11-7/8" x 3-1/2"

If i remember correctly,they retail for around twenty five bucks each.
I got mine through a friend from kellog marine,but i think most of the big box marine stores like West Marine,and Boaters World also carry them.