[Dutchdivco]

Interesting, but not sure its practical for my application.Since we're getting into this, and this IS the intro section, perhaps I should share a little more about my project (2 1/2 years into, just over 1/2 way there).
In addition to wanting a vehicle which can be a daily driver, (1 of 2) and can get as good a mileage as is practical I have an additional requirement; Once every 6 mos. or so, it needs to pull my home, a 1950's era 8'x36' aluminum travel trailer; tandem axle, 7000lbs.Alas, the Plymouth Valiant won't work for this, although seriously considering it for my 'other' car.
My choice is a 1965 Divco milk truck, model 200C. Those unfamiliar with Divco's can Google Divco Club of America. Those slightly familiar may not realise that although they all look alike, they came in 3 different lengths, and 2 different widths.Mine is the 127" wheelbase, (longest standard), and with the widest box. Actually, WB doesn't tell the whole story, as there is 4 1/2' from the center of the rear axle to the back bumper, and 3 1/2' from center of front axle to front bumper; its slightly longer than a full size crew cab pick-up.
The GVW is 14000 lbs, and the stock weight is listed as 5600 lbs.Actually, its not quite as bad as it seems; the refrigeration unit weighed over 1000 lbs, and its gone, as I won't be delivering milk.Mine is whats known to Divco afficianados as a "California" Divco; it left the factory as a "Cab and Chassis Only", and a shop in El Monte, Cal put a fiberglas box on it. Actually, the metal ends just in back of the top of the windshield.(The 5600 lbs is for mthe standard model, all metal, with the box having a double metal framework, metal outside and Galv. metal lining for the box. Unfortunately, I neglected to weigh mine before taking it apart, and I've been unable to find anything telling the weight of these fiberglass models, although its safe to assume they are somewhat lighter.
When I got it, it had a 6:1 gear ratio Rockwell square axle tube rear end; the differential alone was bigger around than my chest, and the rear axle weighed about 1200 lbs. This attached to the frame with leaf springs with 21 helpers, per side.Don't know how much they weighed, but I couldn't lift even 1/2 of the helpers from 1 side.Went back with an 89 GM Corp. 14 bolt 4:1 rear end, weighing 500-700 lbs, attached and aligned with the original leaf and 2 helpers, and the actual support from 3500 lbs airbags.This takes 16" dually rims, instead of the stock 20" 5 hole budd splitrims.Did a disc brake conversion, further reducing the weight.Can put dual rims on, and plan to, ONLY when pulling the trailer, rest of the time running outer rims only.To match wheels in front, replaced stock front straight axle with one from a 79 Dodge Winnebago. Dropped all but 2 of the origina 10 helper springs, and 'bagged the front, as well. Replaced original manual steering box with a power steering box from a 79 1 ton Ford P/U.Am keeping the original "granny" 4 speed, but have installed a Gearvendors Overdrive/underdrive unit on the back of it.When not towing, will give me an overdrive gear for highway driving, lowering the RPM's and fuel consumption. When towing, will give me a gear between 2nd and 3rd, and between 3rd and 4th, although can't use 4th over when towing.
Getting into aerodynamics, I have already constructed belly pan sections, from the firewall to the back bumper.Will make 2 additional sections, from firewall to front axle, and from front axle to front bumper, after I remount body on frame, and replace front body parts.In addition to the lowering due to suspension mods, I am mounting the body 2" lower on the frame.Didn't want to majorly change the look, so rejected the idea of boat tails, etc. Am replacing the headlights with old VW bug headlights, and making a few subtle mods to the front body.The belly pan will form the bottom of a duct, 14" high and 39" wide, running from the firewall to the back bumper. The idea is to take positive pressure air from the front, and duct it to the back to "feed" the draft. I have seen several people speculate on doing this, but no info on anyone who has. So, we'll find out what effect this has.Whew, now I'm tired!Jim