Hello fellow Stovebolters! I'm new to the forum as I just inherited an all original 1954 3600 from my granddad. The truck was purchased new by him, has 70k original miles and was used as a farm truck its whole life. It's "farm fresh". It's been unused for 20yrs and with a few new parts and elbow grease I have it up and running. I've attached a picture for your viewing pleasure! Now time for the question....
As you all know, and I've recently learned, the 3600 has the Eaton HO52 rear end with 4.57 gears limiting its "comfortable" top speed to 45-50mph. After rebuilding the front end I'm looking I be able to cruise on the highway at 60mph (ideally 65-70mph if I replace the rear end). I've been looking for the elusive 67-72 4.10 C20 pumpkin without much luck so I'm considering switching gears and replacing the rear end. I ran across a local complete rear end with torque tube (w/o brakes/hubs) from a 1954 3100 which I believe has the 3.90 gears. This would allow me to install an even higher gear (3.55) relatively easily to get to in the 70mph range. How compatible is the 3100 rear end with my 3600? Would I be able to use reuse my 8 lug axles and drum brakes (just rebuilt) from the Eaton rear end? I'm not against switching to the 6 lug but Id prefer to keep the 8 lug to stay as close to original as possible. If using a 3100 rear end isn't a good option, what is? Any help and direction is greatly appreciated.
Your HO52 is a full floater setup not like the 1/2 ton so no parts are in common there. I went through the same thing you did with my 3/4t gmc. I actually did find a good 4:10 center section and swapped it out no problem but it honestly didn’t make as huge of a difference as I had expected. Could it cruise 60-65? Yes.... I’m running a stock 5.3 in my truck and even that was singing though.....so im sure a stock engine would be too. My next step was to install a borg warner overdrive. THAT made all the difference in the world. I cruise at 65 now at like 2100RPM with a 29.5” tire. You can find those trannys cheap sometimes at swap meets or in piles at the older yards. I see a few pop up on ebay also. Its basically a poor mans gear vendors overdrive but it works great with a 0.7 overdrive ratio. It would effectively turn your 4.56’s into a 3.22 ratio. Its not for everyone but its a option.
******That is a beautiful truck too! Love the long beds and the basic black steelies. Get the original hub caps back on itðŸ‘
I ran a 59 flat bed 3800 with the 4.56 gears at 65-70 routinely, with no problems. Of course, it had the 18" tires, which helped a little, but the main problem is that people who are accustomed to modern engines running just above idle speed on the highway get terrified by the sound of an engine actually working for a living. Most of the sound they're hearing is coming from the fan. Get a pair of earplugs, and a pair of heavy boots. Stand on the throttle and keep up with traffic! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Buy a tach and earplugs. The 3600 came with 15" wheels. Seventeen-inch wheels were RPO XXX with the same 4.46 gear. You could do that with stock hubcaps or buy 19.5 alloy wheels and tires that are tall and skinny. You might even find some 19.5 steel wheels in a wrecking yard somewhere. Just watch the offset and stay around 0"
I run a 3800 w/ 5.13:1 gears. The auxiliary trans has a 17% overdrive which effectively makes the ratio in overdrive about 4.30:1. I have 255/85 x16 tires. They're like 32.5 inches when new. In overdrive the engine spins at 2800 RPM at a calculated 60MPH. I've used various fans over the years including electric (don't bother) and presently have a high-pitch 16" six-blade off some mid-sixties Chev 2-1/2 ton. I have just learned to live with the fan noise. Like Jerry said, buy ear plugs. When you get old like us you'll be glad you did.
BTW I put a Crower cam in it, high lift, 220 duration at 0.050 lift. Gas mileage improved about 30% with just that change. With the stock cam you'll be so far over the torque peak at highway speed that there just isn't any fuel economy. I did the same thing to my Norton motorcycle with the same result -- 42mpg to 55Mpg with a cam change. The Norton doesn't pull hard below about 3000 RPM but then, watch out. The 235 chev will pull smoothly from about 1200-1400 RPM but comes on full song about 2500 or so. I never turn it over about 3300.
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.
My daily driver for a couple of years while I was in college was a 58 Chevy DelRay coupe that I inherited from my late grandfather. It was a no-frills model with a 235 and a 3 speed column shift. It also ran 14" wheels with relatively low profile tubeless tires and a 3.70 rear end gear. At the time Tennessee was just beginning to open up sections of Interstate 40 with a 75 MPH speed limit. Most of us kids considered that to be a "suggestion", so the old Chevy saw speeds in the mid-80's on a routine basis. With a set of 16" wheels and tall tires, there's no telling what speeds I might have achieved- - - - -at least downhill! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
