From some info on Pace Performance's website:
Richmond Gear 4+1 5-Speed
Originally designed and sold by
Doug Nash, the fifth gear was not an
overdrive, but a direct fifth. It
allowed a person to have a fairly high
rear-end ratio of 3.08 and still have a
close ratio transmission capable of
accelerating like a Muncie M21 with
4.11 gears. Richmond gear has
improved on the design, making a 6-
speed called a ROD as well as newer
5-speed with an overdriven fifth gear.
What works and what doesn't?
Doug Nash Corporation had an interesting solution to this dilemma. Make a 5 speed box with a close ratio spread like a Muncie M21 and make 5th gear direct. Again think of what I said about distance between two points. The more stops you make in your travel to get to your final destination the closer the distance between your stops. By adding a lower first speed gear and keeping a direct 5th, you gained more distance, but added an extra stop. The Doug Nash Street 5 speed came with a 3.27 first gear. This allowed drag enthusiants to use a 3.08 final drive and still get good close ratio acceleration. This worked great.
More info from Road & Track:
Some discussion of the 4+1's strength:
As far as shifter location, depends if you want to run a stock console:
Factory Console with a doug nash 5spd??
More info here if you search "doug nash"...
Like this richmond vs tremac