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I asked my machinist the same question when I rebuilt my engine. Chrysler pulled peak hp on these at 3600 rpm, this fellow who had learned his trade in the late 40s and had applied it to old drag racing, roundy round and road racing engine builds told me that 80 to 85 percent of that factory peak rpm was a sustainable cruise rpm. So once you get tires ( I am running modern tubeless radials from Walmart for ease of replaceability) on mine but have after market rims which are 1 inch wider than stock, you need to figure out the over all diameter and plug that in with your rear end ratio into the calculator to see what speed the 80 to 85 percent works out to. Sam beat me to attaching the calculators both of them work well use 3.89 for rear gears in less you know it's a 4.11. It doesn't make much difference my speedo when indicating 65, which according to GPS was 62 over the road, with my tires 225 75 15 on the rear this worked out to 3280 rpm which was in the percentage envelop. My self applied never exceed speed with 4.11 gears was 70. There is really no use in taking them above 3600, the just make more noises and usually expensive ones. Sam's piston speed calculator is a bit more conservative than my machinist so choose your comfort zone accordingly. Most people are accustomed to today's sound proof cars with Windows up AC on engine just over 1500 rpm at 70mph. These cars area lot noiser than modern stuff.soyou have fan noise, tire noise and wind noise which leads folks to think they are right on the edge of blowing up at 50. But they are not really that fragile, just keep your eye on oil pressure and coolant temp. Also watch your oil level but don't over fill. Let it get down to add before you put more in and then area half quart instead of dumping in a full quart. You might find it's leaks less with the slightly lower oil level.

Just a shout out here to Chris Paquin at Andy Bernbaum. Always a pleasure to deal with and has helped me on some tough items, both small and large. He bought out Andy B years ago now and again is excellent. Nice guy.

Might be easier to push low pressure air through the system and check with a soap solution or fancy it up with a home built smoke machine and follow the smoke. Those other two options are both volatile and hard on rubber.

I don’t buy Monroe shocks, Fram filters, or Champion spark plugs......the day of these three entities having top notch products are long, long gone.

Do the trip like the roads were when it was designed Find US 15 SOUTH near Harrisburg, slow down and plan on doing 100 mile segments on the first day then 200, then when you run through full tank.17 gallons. If the engine is decent you should get 15 to 17 mph. It will probably take you a day longer but at least you won't be holding up the nuts down there who read the speed limit as 80, and you won't be surrounded by 18 wheelers. Take your time enjoy the country and if you don't like stop and go through the cities, then jump on the interstate north of town tree or four exits the get off on the south side.. You will be able to drive 60 or so, stop when you need to and find services without waiting for triple A to show up with a flat bed. If your oil pressure is good, the operating temp reasonable and the belt and hoses good shouldn't be a problem. Used as designed they are capable and fairly comfortable long distance cars. I would pull the front drums to check the state of the friction material, and there are no leaks from the wheel cylinders. I wouldn't let any one under 70 screw with the adjustment. They will almost for sure make any conditions or issues you have worse. Infact, go to the resource section of this site and read up on the brakes twice or three times. we went that way on our way from Syracuse to Charlotte years back and the drive through Virginia was scenic and very pleasant. As you get into the Carolinas, look for 17 or 301. As for Florida, you are on your own. I take no responsibility for anything south of Savana. Also, an extra in line fuel filter in the line some where it is easy changed is a good thing. You might want to buy an electric fuel pump and tools and clamps and some zip ties, to install it just for piece of mind. We have about 15 trips of 500 plus miles on our 46. Have been delayed by a broken fan belt and a split metal fuel filter. The seam split where the halves were joined. Gas mileage dropped from 18 to 15 before we noticed the leak at a fuel stop. prepair, plan, then proceed. Enjoy.

He didn’t say it, but...

Good find. I like it. Congrats on another new old Mopar toy. Some day maybe the right truck will find me too!

Here is some back history I am gonna call him “Jim-bob” ?

look up and read on using centric hub and wheels when mounting to an axle/spindle and when they do not match the application of a centric ring.....many feel on these cars with their lower speed and what not this is not a point worth pondering longer than a fart will last in a whirlwind...your call, you can go stud centric if you wish.....but at least you should be familiar with the terms and application when it come to your car and your retrofitting. quick search of terms on the internet nets great articles for your reading pleasure and bring you up to speed on what you are really working with.....

Below is something I wrote up some time back. ********* Somewhat definitive shock information (46-48) Hi All, I replaced my shocks on the 1947 Desoto Suburban (LWB). This car had a build date of Late December 1946. I was surprised when I took the shocks off to realize that the are the original shocks. The front MOPAR part number checks with my part book, the rear does not. However, they have the same undercoating on them that matched the rest of the car. It has a single coat of original factory or dealer applied water base coating. I am convinced that these are the factory shocks. So for your record keeping pleasure: ****************************************** Front Shocks: Collapsed Length: 8.75 Inches Expanded Length: 13.0 Inches Part Numbering from top to bottom as on shock: 12B6 1F8-F0 Made In Monroe Patent No.2.004.380 & No. 2.078.364 PcPd 1121207 Rear Shocks Collapsed Length: 12.5 Inches Expanded Length: 20.0 Inches Part Numbering from top to bottom as on shock: 12B6 1F8-F1 Made In Monroe Patent No.2.004.380 & No. 2.078.364 PcPd 1121208 New Fronts NAPA = 5752ST (Box had LE 10002) New Rears NAPA 94008 ************* Posted December 3, 2016 This week I have been moving parts around. I found the box that had the shocks I took off the 1947 Desoto Suburban when I first purchased it and the 1949 Desoto Convertible when I took it apart. The shocks are MOPAR with the CDPD stamp on them and factory part numbers. They are Monroe shocks. 1947 Desoto S-11 Suburban: Front 1121207, closed 8.75", open 12.875," Dia max 2.125" Rear 1121208, closed 12.5", open 20.5", Dia max 2.125" 1949 Desoto S-13 Convertible Front 1311851, closed 8.75", open 13", Dia Max 2.125" Rear 1311852, closed 12.5", open 20.5", Dia Max 2.125 Interestingly the Monroe cross reference on the 1947 Desoto shows a front part number of 5752. On Amazon or Jeg's they are about $22 each. At NAPA or O'Reilly they show up as from Rare Parts at $200! What a joke... I may have a custom set made for the big Desoto. The shock valves were different according to the master parts book for the heavy Suburban. Custom adjustable shocks may be better for this daily driver than another set of modern Monroe's. The 1947 Shocks are know to be original to the car. The 1949 I suspect may have been changed once. Best all, James

This right here is the key factor. Doesn't matter how fast you can go if you can't choose how you stop.

Yeah, George took two I got to make one. Apparently my reverse hold out doesn't work correctly as it makes funny noises if I don't remember to pull the cable out when I park in the garage and try to reverse out the next time. I don't trust it.

Yes, the piston speed calculator I posted is mean (average) piston speed. Max piston speed will be higher at mid-stroke. This is a little too technical for our flatties but is probably useful for establishing reasonable guidelines. In other words.......don't push these engines beyond what they were designed for if you want long, reliable service life. Speed limits were customarily 45-50mph in the late-1940's---my '48 P15 (no overdrive, 3.91) is in it's sweet spot at 55mph. That's about all the brakes I have, too. ?

Max continuous rpm is usually a function of maximum safe piston speed. As a general rule, 2500 ft/min is a good number to use for max piston speed. With my 218, piston speed of 2500 ft/min works out to 2548 rpm. This doesn't mean the engine can't be wound tighter on the highway, but doing so reduces the margins and and puts it in a corner of the performance envelope that most likely the Mopar engineers didn't like. Here is a piston speed calculator: http://www.hotrodmath.com/pistonspeed-calculator.php You can them use final drive ratio and tire diameter to calculate road speed at 2500 ft/min piston speed: https://spicerparts.com/calculators/transmission-ratio-rpm-calculator And a tire calculator: https://www.rimsntires.com/specspro.jsp Have a good....relaxed.....trip!

Color choices seem limited.

1955 Ford 4 door wagon. Note shape of door tops and rear window divider bar. Fun to try and identify....

Thats a primo car. If it can keep up with freeway speeds, 65 or so why not? If youre rolling down I 95 you should be fine then I 4 to Tampa. Dont get anywhere near Atlanta and I 75

you'd never have that problem with a flathead 6.....

Not sure I want his guns bigger than mine I got 40 years on him and I need every cheat I can get, lol.

That was the era of my youth. We used to pick up running driving cars from the '30's and early '40's for $50.00 and under. Gone but surely never forgotten. Thanks for posting these pics.? John R

Did some more forum reading and someone on another thread said when in doubt go over it again. My spidy sense said ignition but I could not figure it out. So I did go over it all again. Adjusted the points gap and........ Might need a new water pump as there is some noise there but it purrs! Next will be an oil change as I tossed a fair amount of gas down the carb trying to get it to fire. Would have had a cold one to celebrate but -13c windchill was enough for me today. Thanks for all the tidbits! There is nothing more exciting than getting a super deal on an old machine.

Tuning is more than just timing. The carb needs adjusting for the weather as well. A vacuum gauge is your friend here. A brief writeup with links to added info from my website. http://www.yourolddad.com/tune-up

it's the hat...definitely the hat....

My very own first thought! You haven't recently been dropped on your head,have you?

got a little work done this weekend....

According to https://www.t137.com/registry/help/decode.php it's a 1950 B-2-C made in Detroit

A little fine tuning, including a little lube on all of the throttle linkage pivot points, and you'll be ready to drive him down to Tim's BBQ. ?

Ahhh,those were America's Glory Days. Jobs for anybody that wanted one,and you could buy a new car for $1500-2500 bucks and a new brick house for less than 15 grand! Don't remember what the tax rate was back then,but it must have been low because I don't remember hearing anyone complaining about it.

congrats on your new truck Try here https://www.t137.com/registry/help/decode.php post pictures on the truck side ?

I can't recall if I have ever accessed this topic in the past, it has been around for quite some time. I have been messing with cars since I was 14, actually bought my first car, a '40 Chevy three weeks before my 14th birthday which was in 1948. I have had several cars through the years, none of which were DPCD's. Lots of Chevy's and a few Fords. My father preferred Chevy's, however, he had a '37 DeSoto 4dr sdn in 1939, we went to the Worlds Fair in San Francisco. My father did buy a '36 Plymouth in 1943, it was a terrible car, would not start most of the time during cold weather. My father parked the Plymouth in front of a beer bar he hung out in one evening, when he came out the Plymouth was gone, stolen. The car was found out in the desert west of town a few days later, someone had torched it.. I always suspected that the disappierance of the Plymouth was a put up deal. Moving forward to the 1950's, I bought a '36 Ford DeLux 5win cpe in September 1952, the car had belonged to one of my high school teachers, the odometer had 51 K. I still own the car, never intended to keep the car for so many years it just worked out that way. I have driven the Ford over 94,k during the years I have owned it. Through out the years I always had a latent desire to have a 1930 model convertible. I had several chances to buy a convertible, however, I like cars that have warm air and sweet music.. (Heater and radio) which most '30 model open cars don't have. Everything changed for me in 1995, I was in Montana visiting my daughter. Cruising around the farm area around my daughters place I stumbled onto a '39 Plymouth P8 RS convertible coupe. The car had been sitting in an open field for 38 years, a complete car with the engine sitting in the grass in front of the car. After some discussion with the farmer that owned the car, he called it his high school jalopy, he gave the car to me. In my wildest dreams I never thought I would own a Plymouth, leave long a Plymouth convertible. It took me sixteen years to rebuild the Plym, the most difficult project I ever undertook. A significant amount of the body, trim parts for a '39 Plym conv are one year only. Wm

Back in business! short trip with my best friend but, we had fun. Yeah, it was actually an undersized throttle return spring issue ? how embarrassing

I don't expect any issues but if you see any new unusual behavior let me know at info@p15-d24.com.

You are a smart man. Tearing into spare engines to disassemble and learn. I did the exact same thing. Fortunately for me I located tired old, assembled 1950's 218 engine in someone's shop for $100. I bougt it, brought it home, tore it down and learned a ton! I had fun along those same lines with a tranny too. Aside from having a Journeyman old Mopar mechanic here at my side to guide me, I am not sure there is a better way to learn and retain this stuff. Book reading, and lab experiments. So much fun. @ChrisMinelliyou are defintely up a few ranks in my books. Lol. Taking any engines apart in the field will the a pain in the buttocks. They will be rusted and frozen. Rusty valve train and piston rings are a struggle to get apart at home in your garage. Let alone in a field with limited tools and resources. You could get some ¾" plywood to lay down and support an engine hoist. Can you get your truck in there close, so you can hoist a pulled engine into the back? Keep in mind to get the engine out, you nee to pull the tranny. To get the tranny out you need to pull the driveline, possibly interior floor pans, etc... Easy at home. In the sticks where they filmed the Blair Witch Project? Not so simple. You have a soft spot probably for old Mopars. It is hard to see them sitting there rusting, mother nature slowly taking them back. In reality you are probably better off to seek out an old flathead Mopar engine in town somewhere. Set up a search for "flathead" in Facebook marketplace. They will send you a notice when anything pops up. An engine will come up. They literally built and sold millions of these engines. I'd be surprised if there is not one million of them, not yet scrapped and or melted down.

Lol, thread title is “been a different day” and you mentioned a mustang owner with “identity issues” nope, sounds about right ?

Hold out for some tri-tip- ggdad1951, he does the cooking, And - drawn butter garlic shrimp over the BBQ. He IS a good cook! Do not travel that far cheap without a good fill up!! ?? DJ

Oh Merle, you know me soooo well. ? my poor neighbors, as soon as the wildfire smoke clears Brent stinks up the neighborhood, LOL told them I’ll wait until they’re not home to fine tune it