Some here argue the need for a 6-speed over a 5-speed, or two overdrive gears. Well, i'll just go ahead and argue the need FOR them.
Not for everybody, but if you like to drive FAST... for long periods ov time, then you've gotta gear for that (lets just assume that you're not just steeenking rich). I currently daily drive a 96 Mustang GT (4.6L, 5-speed, 3.27 8.8"). In my 72 Charger... i HATED the 3.23's. What a useless ratio. Does NOTHING well. Not good for drag racing unless you run a Caddy 500, not good for MPG unless you never go over 50MPH. Its a better gear in my GT, as the 4.6L is smooth as glass and VERY efficient, but in the average classic car, 2600RPM at 60MPH is excessive. Further, who actually drives at 60 on the highway? most do 70 or more, me... a lot more. One trip i make infrequently averages around 95MPH. In my car, 100MPH in 5th is 3000RPM. The car seems to run well and use pretty much NO gas at 2000RPM highway. Granted, the 4.6L doesn't make enough torque to pull a 3400lb Mustang 100MPH at 2000RPM, but it sure as hell doesn't need 3000. A big block anything could easily pull 100MPH at 2K. A big block or even an old-school (non-Magnum) small block wont be happy at 3K either, so lets bring that down too. Further, at times i only limit myself to 100MPH because ov the mileage. Give me more gear (legs) and i'll get to point-B faster.
For anyone cringing at the Mad Max visuals here, one can easily substitute an open-course road race here.
Thats one point. the other... is gearing. In my Mustang (to make my point), a common mod is a 3.73 rear upgrade, or for the 7000RPM 4-valves, a 4.10, 4.30 or even (many will vehemently argue) a 4.56 gear upgrade. For a drag racer, sure the single OD will bring that 4+ gear down well into the 3's to drive to and from the track... and do some peelers on the strip. But for the guy that wants it all, the T56 can let you have 4.30 or 4.56's at the track/street drags, and still have around a 3.27 gear for the highway (thats a 4.56 gear, that runs 2000RPM @ 60MPH). Thats a LOT ov range. For those that argue the 1st gear becomes useless in a steep-1st T56 with 4.56 gears, the Mustang guys will counter that well... if it wasn't all-out faster, they wouldn't be doing it. Most cars on Moparts wont need anything over a 4.10 rear, but with 'only' a single OD speed you're still making a lot ov noise on the highway. Remember, we are living in the age ov having your cake and eating it too. Not wanting to take advantage ov that is like sticking to 40 year old cam grinds when there is soooo much better stuff available now... just because 'its good enough'.
My plan: light car, 7000-7500RPM small efficient V8, T56, 3.27's. That'll give me the 1st gear launch i'm used to in the GT more or less (enough for me), and basically, a whole 'nother gear on top ov the 5th when i'm doing 100MPH and either want to go faster (in my car the engine WILL pull the gear/speed) or just save some gas at 'cruising speed'....
Granted... my points will be for extreme needs, but i would still argue the fuel savings if you like to drive over 70MPH for periods in a car with a big or pre-Magnum (read: inefficient) engine. Sure i'll get the "oh well if you're looking for MPG buy a Honda!" retort... which... is almost always coming from people who drive their cars only on sunny weekends. Whole lotta big scary 440's sitting under dust because they're too expensive and annoying (at sustained highway RPM's) to run...
