Howdy H.a.m.b.er's, Can anyone give me some advice on gear ratios? I have "56" ford P 500 parcel delivery van that has a Rockwell Standard C-100 rear end sporting a 5.83. This is way too low! The truck has a 223 six engine that runs real nice. I would like to take it on the freeway (in the slow lane, 55ish) Hauling a fair amount of weight. What would be a good ratio for this? And will it fit in a C 100 third member? Thanks all, D.O.G.
You no doubt realize that if you change to a higher gear ratio (lower numerically) that the effect will be the same as if you reduced horsepower. With the size, weight and wind resistance of your truck, plus cargo, with a 223 six, there isn't much horsepower or torque to spare. I have no idea what fits the rear axle housing now in your truck, but I would imagine some diligent research will unearth some info about ratios available, and some of their applications. A truck salvage yard would be a good place to inquire about that. My guess would be 4.56 or so would be about as much as the engine would handle with the aforementioned load factors. Ray
Thank you Ray, I did not realize the loss of horse power was that relative. I will do some more sussing. Christopher
A 4.10 or 3.90 gear and a mild hop-up of the 223 might work - if you can find a dual carb intake and split exhaust for cheap you will get an extra 10-15 hp, enough to get you faster with a taller rear gear. (Just guessing though)
You will have a hard time finding anything for that rear as it has been obsolete for 40 years. And I really doubt you could pull any lower ratio with that engine. If you gota go faster you gota get more power ,V8 or better yet a Cummins 4 or 6 BT with a 5 speed OD. Those type trucks were city delivery trucks never designed to run down modern freeways.
A couple of things to consider, like previous posts not too low because not enough power there once your up to speed. Try cliffordperformance.com for some 223 hop-up stuff. The rear end itself probably doesn't have anything much better than possibly 4:56's. If its a dual wheel setup, you probably also have 6 lug wheels that might also be 17.5 tires size. If you lucky they might be currently 16's, which will give you a lot more choices. What i would do is look for a Dana 60 (single wheel) or Dana 70 (dual wheel) with something like 4:11's. They also would have 16" tires a more modern 8 lug wheel that most trucks had from 57-96. A lot better on the highway and 55 friendly more than what you have and if you still want a little lower RPM's go with a taller tire. If you would do this you should probably also look for some front spindles that would also be 8 lug so you could have all the same wheel/tire size. Just my 2 cents. Michael
Thats a city truck. My daily worktruck '68 grumman has a 300-6 and 4.56, not even close to an interstate worthy. She runs around town pretty well but winds above 4k to do 50+mph. Does the job it was made for very well I might add.
I thought the same thing too a city delivery truck with those gears. I guess the truck has 5 lug wheels on it?? What size are those tires. Michael
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