Mike:
Take a look at
http://www.368s.com/tools_rpm.phtml for a gear ratio calculator, just plug in the numbers and see which combination gives you what you're looking for..
ERA advises to keep the first gear ratio to one that will produce no more than 10 mph per 1000 rpm in first for a street machine. With the 3.27 first you can go as high as 2.88 for the final drive ratio and still be streetable. 3.31's seem to be very common with the Tremec and Richmond trannys.
DonC