Found a desoto hemi

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21willys

Well-known member
Joined
Mar 8, 2011
Messages
2,751
In my recent junk yard hunts I found a hemi still in a desoto. I know nothing about these motors other then that some can be worth a little bit. What engine should this car have in it? Is it worth much of anything?

 
Know what year it is??? I got an old Motor manual here in my lap that covers from 57-61 that shows v8 in 57...some had 270hp Firedome 341ci. Fireflite 295hp-341ci, Firesweep both in 245hp and 260 hp 325ci.
58 had Firesweep 280hp-350ci, Firedome 295hp-361ci, Adventurer 345hp-361ci with 2 4s
59 shows 290hp-361ci,Firedome 305hp-383ci,Fireflite 325hp-383ci,Adventurer 350hp-383 which had 2 4s
60 had Fireflite 295hp-361ci, Adventurer 305 hp-383ci
61 shows 265hp-361ci
I think the Firedomes were hemis but not sure of the other motors.
 
Hello,
For good information on that Hemi , as well as i.d. Info, go to
HotHeads research and racing.
Those motors look cool in a hotrod, but are heavy.
 
Desoto, Chrysler, and Dodge all had hemi's, and from what I remember reading, not much interchanges between brands. I think the DeSoto version was kinda a orphan, not much out there in the way of parts, had their own bellhousing/ trans bolt pattern, but I might be wrong on that. Chrysler is most desired, with the smaller Dodge Red Ram engines next, Desoto last. MercuryMac will probably know more about them than I do, I think he is a Mopar fan....
 
I also have heard the Desoto engines are hard to find parts for.
In any case as bruno said, if the price is right grab it.
There's always a buyer for a hemi.
 
A 331 and a smaller on on Craigslist in Omaha right now with transmission
for cheep in car parts by owner... also a 1957 364 lincoln for 500 bucks

There is a flathead v12 too but the guy is smoking his own dope.
 
Eric, my Son Don bought a 291 Desoto Hemi some years back, and when I called Hot Heads to ask if it was any good they said "There are no bad Hemis, all of them are worth doing."

I would grab it if I were you.

Don
 
The guy who has it has no idea what he is doing. He will price one thing at ten times what it's worth and the next a fraction of what it's worth. He priced the hemi with auto trans at $1600-1700. To much to gamble on for me. It liable to be a complete boat anchor.
 
Look on the front of the block, on top, right behind the water pump, facing up, there might be some numbers. These will tell you the ci. displacement and possibly the year. I was hoping it had a standard transmission so I could tell you to make sure you took the bellhousing and trans with the motor. Probably a Mopar, pre-1962, Poly V-8 bellhousing and flywheel will fit on there, and maybe a flathead six bolt pattern will be the same, but this is just my theory and not proven yet------until you buy this unit and get at fixing it up.:D
Good luck.
 
Found another one

I was checking out a new yard today and found another one. A Chrysler this time. I believe it's the small one. The car was about a 53.




And at about half the price as the other one and it comes with the car!
 
How do you find all this stuff [S
[dr

I've travelled 25,000 miles in the last two months and have been coast to coast, border to border. Every time I hear of a yard with good stuff in it I put it on the map and I stop at it as soon as I'm in the area. The first hemi is in Colorado, the second one is in North Dakota. As soon as I have time I will update my pic thread in the bs lounge.
 
As soon as i hit submit the other side of my brain "he travels all the country you dummy"
Again if you in my neighborhood i'll buy lunch. [cl
 
If you want a Hemi, I'd go for the Chrysler one. Less money up front, easier to find stock and go fast parts. It might even be the sought after 392!
 
Long read but interesting info on the early Chrysler hemis...


The Origin of the “Hemi” Motor
Hemi Motor Development and Description
In 1951, Chrysler introduced their new line of V8 motors, popularly know as the “hemi”, because the combustion chamber was fully machined into the shape of a ½-dome or hemi-sphere; I will refer to this motor and its direct descendants as Generation I, Type I. This was the first use of this design in an American passenger car, although the principle had been in use in other applications for decades.
The intake and exhaust valves were located on opposite sides of the chamber at 90° to the cylinder bank axis, so separate individual rocker shaft assemblies (two on each head: intake and exhaust) were used to control all sixteen valves by the same camshaft.
The hemi motors produced excellent power, but the expense, additional parts and complexity of the valve gear, as well as the weight of the extremely wide cast-iron heads were not a practical choice for all vehicles.
The cylinders were placed in two banks (rows) of four cylinders each, arranged (as is common practice) at 90° to each other; each is 45° from the vertical axis.
Additional Hemi Motor Development
After the original introduction (limited to Chrysler cars only), DeSoto and Dodge developed and introduced their own unique hemi motors in 1952 (Type II) and 1953 (Type III), respectively.
These motors were smaller than the Chrysler hemis by virtue of smaller bores, closer spacing of the bore (the distance between adjacent cylinders in the block), main bearings (shown right; main cap bolts are shaded) & cam bearings, shorter strokes and lower engine block cylinder banks. In 1964, Chrysler introduced yet another hemi motor (the largest: Generation 2) developed from the “RB” and unrelated except in general theory to the earlier types.
Because of these differences, almost no major parts can be interchanged between brand names or “families”.
In the Chrysler literature, hemi motors are also called dual rocker shaft (“DRS”) while poly motors are called single rocker shaft (“SRS”). The lower-priced 1955-58 Chryslers used a polyspheric motor developed from the Chrysler hemi. No Plymouth used a hemi motor until 1964.
Cylinder Bank Height
As development progressed, larger displacement Type I motors were introduced, the largest using an engine block with taller cylinder banks to permit increased stroke.
Chrysler engines have only two stroke lengths; all “low deck” motors have the shorter stroke crankshaft and shorter connecting rods, and all “raised deck” motor have the longer stroke and longer connecting rods.

The Chrysler raised deck motors had their tappet bank angles re-aligned closer to vertical from 61.5° to 59°. This change aligns the tappets with the new (higher) rocker arm positions and maintain proper valve train geometry. The other Types also used different tappet bank angles for their low deck vs. raised deck engines.
Cams should not be interchanged between low deck and raised deck motors of the same family since the new tappet angle will have the effect of “clocking” or rotating the lobes of each cylinder bank in opposite directions, causing each bank to have slightly different opening and closing points of valve operation with the same duration.
This change limits interchange of intake manifolds and heads between low and raised deck blocks to some degree. However, despite the height difference between the 331-354 and 392 blocks, intake manifolds are interchangeable between motors (except for port size) since the 392 intake ports are extended, so that the port-to-port width remains constant. A 392 using early heads will require a wider manifold or spacers. No manifolds were produced for the reverse combination (331/354 using 392 heads), and will require a manifold to be modified, although I’m not sure if this is possible.
Chrysler Motors Grouped by Deck Height
Low Deck, Short Stroke, Short Rod Raised Deck, Long Stroke, Long Rod
Year Size Year Size
1951-56 331, 354 1957-58 392
Component Function
Valve Train
The hemi motor’s tappets and pushrods are accurately “pointed” at the rocker arm ends for best mechanical efficiency. The intake and exhaust rocker arms are different in length, and pivot in opposite directions.
A true hemisphere is a 50% segment of a full sphere (width = diameter, depth = radius), but the Chrysler hemi’s combustion chamber shape is not a “mathematically correct” hemisphere but a partial section, since the chamber depth is less than the radius of the theoretical sphere, and the chamber width is less than the diameter of the theoretical sphere; the theoretical sphere being the shape from which the actual curvature of the chamber wall is taken.
Although aesthetically pleasing, the Chrysler’s deep chamber (where the depth is a large percentage of the radius, although less than 100%) has proven not to be the most efficient shape, and later motors (such as the “RB” based 426 hemi) used a lower percentage of a hemisphere of larger diameter.
Generally, the width of the chamber is equal to or slightly less than the bore diameter; this provides room for the largest valves. However, chambers of smaller diameter (but not larger) can and have been used successfully.
Hemi Advantages
The hemispherical shape has the lowest “surface to volume ratio” of the possible choices. This means that the amount of heat and energy lost by contact with the surface of the chamber is smaller than any other practical shape with the same volume. This factor was given more importance at the time than is held by current opinion, which favors more shallow chambers.
The hemi combustion chamber shape is also conducive to intake flow from the valve seat, as the chamber wall offers less obstruction than most other choices.
However, the large chamber volume requires a large compression dome on the piston to achieve a high compression ratio. This dome adds to piston weight, obstructs port flow when the piston is near TDC, obstructs flame travel, and loses back part of the surface to volume advantage referred to earlier. This is one reason why the hemi is more successful in supercharged and turbocharged applications than normally aspirated: the smaller and lower piston dome for the 8-1 compression ratio (favored for boosted operation) is less of a problem than the tall and irregularly-shaped dome on a 12-1 piston.
Port Characteristics
In a “wedge” motor, the intake valve stem angle is inclined at only 6-23° from the cylinder bore axis, while the intake port is nearly 90° from the bore axis, so the intake port shape must include the remaining 67-84° curve, which reduces flow. Since in a typical wedge motor the intake and exhaust valve stems are parallel, the wedge exhaust valve is inclined against its port flow direction, so the port curve is closer to a 96-113° curve (this is not as critical since the exhaust flow is under pressure).
Hemi valves have an “included angle” (between the two valve stem axes) of 53°. Each valve is inclined favorably from the bore axis by 50% or 26.5°, so the port curves are reduced to only 63.5° (the valve stem more closely follows the direction of the port centerline), and flow is improved.
 
As a note: there is another chamber design variant in which the valves are not parallel to each other, but the shape is not a hemi. This type includes the Chrysler, Dodge and Plymouth “poly” motors (331, 270, 318, etc.), Chevrolet big block (396, 427, 454, etc.), Ford Cleveland & Boss small blocks (302, 351, 400), and Ford 385-type big blocks (429, 460). The valve stems in these motors are inclined both to the bore axis, and to the other valve.
Valve Train
The intake and exhaust valves were located on opposite sides of the chamber at 90° to the cylinder bank (directly across from each other), so separate individual rocker shaft assemblies (two on each head: intake and exhaust) were necessary for all valves to be controlled by the same camshaft. The tappets (lifters) were placed in left and right banks to align accurately with the rocker arm ends. Both intake and exhaust pushrods closely follow this angle, which insures optimum mechanical efficiency and minimal lost motion: there is almost a straight line between the cam lobe, the tappet, pushrod and rocker arm. The pushrods enter the heads at approximately the same place, but the rocker arms operate in opposite directions: the exhaust rockers pivot out towards the exhaust valve stems, while the intake rockers pivot back in towards the intake valve stems. Since the pushrods’ point of entry into the head is nearest the intake valve, the exhaust rocker arms are longer and heavier.
Cylinder Head
In theory, the hemi head design permits better port location and alignment (compared to a wedge motor). The intake valves can be inclined to improve the “down-draft” angle of the port (as in a wedge), but the exhaust valve can be separately positioned to incline more favorably to the exhaust port (in this case, 26.5°, an improvement over the 6-23° reverse-inclination of typical wedge exhaust valve).
A disadvantage of the hemi valve arrangement from a thermodynamic point of view is that the combustion chamber shape does not offer flat surfaces to the piston dome to form “squish” or “quench” areas to provide turbulence and knock suppression. In a low compression motor using a flat-topped piston, which does not rise above the cylinder @ TDC, the shape is acceptable where cylinder pressure is low to moderate. This not only limits the motor’s compression tolerance considerably, but also makes the dome shape of a high compression piston asymmetrical and complex, as the dome must fill part of the chamber @ TDC but not touch, or even mask, the intake or exhaust valves or spark plug.
The valve seats are located directly across the head from each other and 90° to the bank axis, not parallel to the cylinder bank axis (as in a wedge).
Pistons
All original pistons are cast aluminum alloy. Most have slight compression domes (area of slightly smaller diameter than the bore) with two valve clearance notches. All have “floating” piston pins with retaining clips.
Pistons are marked for direction, as the piston pins are offset to the rear; be careful to follow the instructions for which way the mark goes - usually towards the front of the motor.
Block
The engine blocks are excellent quality of design, material and workmanship. All were “two bolt main cap” types, meaning the crankshaft main bearing caps securing the main bearings to the bottom of the block used two bolts for each cap. Please note that some 1955-58 low deck blocks (potentially) intended for Saratoga or Windsor 301, 331 or 354 poly use will have the pushrod clearance holes enlarged into a "figure 8"; these are perfectly safe to use.
Connecting Rods
Each engine family, stroke length and deck type has its own unique rod. All rods are high quality forged steel, and more than adequate in strength for the original power produced.
Crankshaft
All crankshafts (including the 1955-58 Saratoga & Windsor 301, 331 & 354 poly motors) are high quality forged steel with rolled fillets, and use an un-threaded 8 bolt (obsolete pattern) flange.
More importantly, the pre-1962 flange for the 1956-61 A-466 iron Torqueflite protrudes farther out of the block than the 1962-* flanges. This precludes direct use of a later transmission or bellhousing, as the crankshaft is too long, and a 1962-* A-727 Torqueflite bellhousing will be short of the correct position and require an adapter.
DeSoto hemi, Dodge hemi, Dodge poly or poly “A” crankshafts cannot be used in Chrysler motors.
 

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