At the risk of hijacking this thread, please allow me to jump in with an observation and a question.
It would seem to me that when selecting a transmission to begin with, that one should consider not only the horsepower and the tire size, but the entire package: engine horsepower, torque characteristics, anticipated driving style, axle ratio and tire size, but also vehicle weight, windage, towing needs, useage, and the need for economy.
That said, it should be noted that no engineering process is based on absolutes; it is instead a series of compromises and trade-offs, and availability of off-the-shelf components is a factor because the strengths of one component can make up for weaknesses in another.
The debate between the 700R4 and the 2004R sounds to me much like the old arguments between close-ratio and wide-ratio four-speed manuals we used to hear years ago... Sure, the close-ratio four-speed was better for performance once you got it rolling, but the wide-ratio trans was simply easier and more pleasant to drive in realistic day-to-day situations. Massive engine torque and clutch-slipping made up for the lack of a low enough starting cog in the CR trans. A wide torque band made up for wide gear spacing in the WR trans.
To me, it all seems to come down to a realistic appreciation of vehicle usage as an entire package.
I'm about to start on a restoration/repowering of my '69 Chev 3/4 ton pickup, currently equipped with a 350/TH400, and with a 4.10 axle and 16" wheels. I plan on installing a turbocharged EFI 292 in front of a 700R4. This truck will continue to be a working truck, generally driven only when loads are to be hauled. Most loads are small, but it is not unusual for me to put 3000 pounds of rock or lumber on board, or to pull a 10,000 pound trailer.
I hope to acheive somewhat better economy when lightly loaded despite the non-aerodynamic shape, but don't want to give up the ability to handle heavy loads when necessary. I've picked the 700R4 for the overdrive, but also for the 3.06 first gear to help get this 5000 pound truck moving and to get the turbo spooled up. I've also picked a turbo with a 1.10 A/R because I don't want tremendous torque below the middle rev range or want large exhaust restrictions at higher RPM. Because of the 3.06 first and the 4.10 final, I'm not seeing a need for an elevated stall speed on the convertor. I also assume that the engine's mid-range boosted torque should allow it to handle the large speed variation between gears, making the truck reasonably quick and fun to drive when unloaded.
I think that all too often we give advice based on a single point of view, whether that be strip performance, bragging rights, grocery-getting, or cruising main street or whatever else and forgetting that vehicles will be expected to be many things at different times. Based on the entire package then, do my choices seem reasonable? Based on George's plan for a responsive 3000 pound (or so) street car, what seems reasonable?
Fire away, gentlemen...
