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souped-up flathead 6
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59savoy
Posted 2004-09-21 7:31 PM (#13373)
Subject: souped-up flathead 6



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i'm wanting to hop up the flathead in my 59 savoy. any clues about speed parts, manufacturers, etc.? what kind of horsepower is possible with normal aspiration? what about exhaust?

lots of people have hot v-8s, i've never net anybody with a hot mopar flathead six. is it possible? is it cost effective?

i think it would be pretty cool if people learned that F**d and hudson didn't make the only hot flatheads.
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JERSEYBOB
Posted 2004-09-21 10:30 PM (#13385 - in reply to #13373)
Subject: RE: souped-up flathead 6



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Boy, I wish I could help you. I think there was a post about a guy who put a turbocharger on one not too long ago. anybody remember?? Anyway, some of the old timers might know of speed equip, but I sure havent heard of any. A couple of brief things I CAN tell you is this. They've got low compression, I think aroud the 7.5:1 area. raise compression; raise power (and heat) technically I guess you could shave the head for compression and all the things that go along with that. custom pistons are not impossible either, but could be more $ than your willing to spend. Of course a cam could be ground from a stock one, and theres always carburetion and exhaust. Or,... just leave the compression alone, throw a blower on it and see how long it lasts. Someone also just asked about an aluminum head for one, they may have been available.
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Bugman
Posted 2004-09-22 9:48 AM (#13458 - in reply to #13385)
Subject: RE: souped-up flathead 6



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A flat 6 won't make much HP, but mountains of torque(relitivley speaking)
Talk to tractor pullers. they use Chrysler Flatheads in Massey-Harris tractors and have all kinds of speed parts for them. Every few months, dual carb intaked come up on e-bay. Fenton and Offy, and a few others made'em.

Talk to this guy, tell him I sent you: pete@andersonarc.com He's got a good buildup on his website(which I can't find right now)

Go here: http://www.inliners.org/cgi-bin/ultimatebb.cgi
It's a whole board dedicated to inline engines, and they have a Mopar Section.

Flat 6's respond very well to turbocharging, as well as dual carb intakes and performance exhaust systems. 150 HP is fairly easy to get without a turbo, more than that you'll have to work for. if you have the engine apart, you should have the crank cross drilled to improve oiling to the center rods(cause rod oiling sucked from the factory, and will lead to spun bearings). Porting the block is easy to do, and will gain you some HP, but you have to know what you're doing. Read up on flathead porting before you attempt it. DON'T relieve the valve to cylinder area like you would on a F**d. Have everything balanced by the machine shop.

Most of the tricks that will work on a flathead F**d will work on a flathead Mopar. Any questions, let me know.

-Jeff

Edited by Bugman 2004-09-22 10:03 AM
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Bugman
Posted 2004-09-22 10:01 AM (#13463 - in reply to #13458)
Subject: RE: souped-up flathead 6



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P.S. you can make anything go fast. It's just a matter of money and effort. You won't get into V8 performance levels, but you wouldn't be one of the sheep following the croud either. You will have to research what your doing, and hunt for info because it's not a mainstream motor. That's why I recomend that you find Tractor Pullers. They still use the things in a performance application. You can do it, it will be more of a challenge than it would be on a V8, but that's what makes it fun.

-Jeff
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DeSotohead
Posted 2004-09-22 11:21 AM (#13481 - in reply to #13373)
Subject: RE: souped-up flathead 6



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I know a guy in Florida that has a true "Legends" racer (34 Plymouth with a big DeSoto L-head 6 in it.
He has an Edmunds dual carb intake (forget if 2x1s or 2x2s) plus a home fabricated header exhaust.
This thing actually races in the Florida, South Georgia and South Alabama dirt track series for those cars (versus the motorcycled-engined Legend shrunk scael cars).

I can contact him and see what he has done to his engine, if you want.

REMEMBER...This is a REAL race engine build-up, not hot-street!
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59savoy
Posted 2004-09-22 11:32 AM (#13484 - in reply to #13373)
Subject: RE: souped-up flathead 6



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great, now i've got a place to start! i should say i want the car to be a streetable driver for fun.

we've got a round-and-round dirt track at kellyville, about 30 miles from here. i'm not going to go that route; i want to enjoy the fruits of my efforts longer! besides, who would i race?

there is one guy out there who has a 300 inline F**d six. the front wheels come off the ground. that's pretty damn good.
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Shagrat
Posted 2004-10-17 9:22 PM (#15554 - in reply to #13373)
Subject: flathead 6 performance info



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Written by David Pollock. Excerpted from Chapter 14 "L-6 Engine Rebuild"in Dodge Pickups: History and Restoration Guide 1918-1971.

Stock rebuild:
This is a straight-forward job of returning all wearing and gasket surfaces to factory specifications. Done correctly, a rebuilt engine should be as good or better than new — no green castings, that’s for sure! The services of a machine shop specializing in engine work will be required. If you are prepared to do the dirty work and reassembly, a rebuild can be done for about $600, bur don’t be surprised if it runs to twice that amount.
Most people will want to use the engine block that is in their truck. Check the block for signs of trouble before you are totally committed. While cleaning, look for the cracks that are most likely to occur on either side of the distributor due to a frozen water jacket or through the fuel pump opening from careless handling or a collision. Check the area around exhaust valve guides, looking down into the block after removing valves. Chrysler L-6 blocks were not prone to cracking, but it pays to check. A careful visual inspection is usually sufficient. If you suspect a crack, fill the water jacket with kerosene and the crack will show up for sure.
If the engine has unusual wear or damage to the crankshaft, check the alignment of the main bearing seats. A problem here an be corrected by align-boring. Do not reuse a connecting rod that has spun a bearing shell. Check all rods for alignment and trueness of the bearing seat. A simple test for rod alignment is to swing two rods on one wrist pin and see if any light shows between the big-end flanges.
Chemical cleaning of the block is a good idea. Bear in mind that the cam bearings will be destroyed in the process so have a new set on hand before you start. Replace all core plugs with new ones.
Before boring, choose an oversize piston that will compensate for cylinder wear and have these on hand.
If the engine has had a history of head gasket failure, it would be wise to deck the block. This is the same process as cylinder head resurfacing. It’s a lot easier to do this now than later, and has the added bonus of narrowing the valve seats a little.
The rest of the rebuild follows standard procedure. You would be wise to use the later, rotor-type oil pump as it pumps a higher volume of oil. Watch for oil pipe on prewar engines; the way that looks right, isn’t! The counterweight next to the number 3 main bearing will hit. I learned this the hard way and even then I almost installed it backwards a second time. Follow tightening specs carefully.
A low-budget balancing job can be done right at home with an ordinary balance-beam scale. Find the lightest piston and pin assembly, and remove material from the others until they are all the same. Do the same for the rods. If you really want a smooth runner, a professional, dynamic-balance job, including fly-wheel and clutch, is in order. That’s a job for a pro, but it may be worth it if your engine has been built using parts from many other engines.
There is little left to luck in this approach to engine repair. Retighten the cylinder head and break it in carefully. With routine maintenance it should last as long as you can afF**d gas to run it.
Incidentally, there is no reason why these engines will not run well on unleaded gas. The stellite seats on the exhaust valves were meant for long, trouble-free service. I ran one engine for years on no-lead propane without any problem at all.
Parts interchange:
On all sixes, except certain industrial and truck engines, valve guides are interchangeable, as are exhaust seats, wrist pin bushings and oil pumps. Rear oil seals are of two or three designs and are sometimes interchangeable, but watch out for a slight space if you are using a later seal on the 201. This space is between the metal seal holder and the block, and can be filled with silicone. Gaket sets are of two sizes for the two different-size blocks. There is an extra water passage at the front of the head on 1951 and newer engines; this is part of the later bypass system and eliminates the need for extra plumbing.
Crankshaft bearings are the same for all 3 1/2" bore blocks. The 3 3/8 and 3 7/16" bore blocks share slightly larger bearings. Crankshafts within each block size can be interchanged, but you must use the rods that match the crankshaft. I have often put a Dodge crankshaft into a Plymouth block for an extra 13 cubic inches.
Performance modifications:
The Mopar sixes will respond to all the traditional hot-rod tricks and they needn’t spit their insides all over the street, either. As you read on, you may think that I have a trophy room full of bent and broken con rods. Not so! I blew my one and only rod bearing on a cold January day in 1959 while driving a 1935 Plymouth coach on farm roads. I was not old enough to have a license, nor did I recognize that clunking noise. I learned fast and have gone straight ever since.
If you’re going to boost the horsepower and performance of your Dodge truck L-6 engine, you’ll need to improve the oiling. This is done in several ways. The first is to increase the size of the groove in the main bearing shells. The technique here is to clamp the bearing shells in a four-jawed lathe chuck by bolting two surplus center main caps together. Make the groove in the bearing shell approximately 3 times as wide and twice as deep as that cut by the factory. It will then match the diameter of the oil hole in the block. This should be done to all 4 mains.
With a greater volume of oil coming from the larger grooves in the main bearing shells you can plug the squirt holes in the rods. This little hole tends to deflate the oil cushion around the bearing, especially during the power stroke. With the added oiling there will be plenty of throw-off for cylinder walls.
It is also prudent to install a new rotor type pump. Putting a 1/4" spacer behind the relief valve spring gives an additional boost in oil pressure.
With these modifications, the oil pressure gauge will show about 40 lb at idle and between 60 and 70 lb at 30 mph. If your block has a full-flow filter as later Chrysler and DeSoto blocks (to 1954) do, great! If it has the bypass type, make sure it is correctly hooked up. The drain goes from the bottom of the canister through the pressure relief valve (hole faces straight up). Be satisfied that it is not reducing pressure.
If you are choosing a crankshaft, use one from 1955 or newer. If it is still standard, so much the better. Don’t forget you can interchange shafts in the 217 and 230 engines as long as you use all the rods that go with the crankshaft. Same with all 3 3/8 and 3 7/16" engines. Early shafts have 4 bolts in the flange, later have 8, but all flywheels fit, with the exception of some Plymouth Hydrive models. There is a ring-gear-starter change between 1956 and 1957. They do not interchange. Select components that match the bell housing you are using.
Compression on these engines can be raised as high as 10.5:1. In one case, I planed an Edmunds aluminum head as far as possible. Unfortunately, head gasket failure was chronic, but it was fun while it lasted!
You will probably wish to be conservative — say, an 8.0:1 compression ratio, which was stock for 1959. It helps to polish the chamber in the head before starting out. Compression can be raised by 3 methods: first, by milling the stock head 0.060 to 0.125"; second, by installing a head from a later engine; finally, by installing an aftermarket head such as Edmunds or Fenton. If you use a later head, watch for the extra water passage on engines from 1951 and later. When installing a later head on an earlier engine the later gasket must also be used. On heads from 1956-1959, the temperature gauge fitting is smaller, but it can be drilled out and retapped to use the fitting for your truck.
Aftermarket heads are rare, but not impossible to find. I purchased a brand new fenton for $75 within ten miles of home and found a good used Edmunds at a swap meet for $80. Unfortunately, these vintage speed parts are not being remanufactured. With these heads use AC44FF spark plugs.
Watch out if you are swapping a head from an engine with a different bore size or you may wind up reducing compression. For example, a 3 7/16 bore engine has a larger chamber than a 3 3/8 bore engine. On the other hand, you can raise compression this way by reversing the operation. If in doubt, "C.C." the chambers.
Good gasket surfaces are an absolute must!
Years ago, I carried a spark plug wrench so I could open up the gap of number six spark plug after every 5500+rpm run. It is hard to look cool doing this on the side of the road, so check valve clearances.
Don’t forget the tightening sequence and retighten the head as soon as it’s warm and again after 500 miles.
Better induction:
Better induction really wakes these engines up— even a two-barrel carburetor as used on 1957-1959 Dodge cars helps. Edmunds and Fenton both made manifolds for both sizes of blocks, or you can make a manifold using your stock cast-iron one as a base. Three-ton trucks used a dual carburetor manifold which also had a dual-exhaust headers. It works well, but is bulky and heavy.
Carburetors are a cut-and-try proposition as big is not always better. I would recommend the Zenith carburetor as found on International trucks of the 1940s. They are beautifully made with a brass-piston accelerator pump and have replaceable venturis, which come in a number of sizes. Jets also come in several sizes, assuming you can find a source. Studebaker used a slightly smaller version of the Carter Ball and Ball which would not work well on a dual-carburetor system.
Exhaust:
Any improvements will help. A simple split manifold is good. Fenton headers are nice to look at and work well, too. Headers can be made from two stock manifolds or from tubing. The fact that the engines have six exhaust ports is a plus there. Put on nonrestrictive mufflers (remember the Blue Bottle), and a good, clean exhaust system and this part of the job is done.
Porting:
The most significant improvement to be made here is the matching of the ports with the manifold passages. Careful use of templates and a rotary file will do this job. This is a simple, but exacting, operation as carelessness can ruin your block. Even a stock rebuild will benefit from port matching.
Clearances:
Slightly greater clearances are desirable in a performance engine to insure good lubrication and allow for expansion due to greater heat. Allow 0.004" for piston skirt clearance and between 0.0015 and 0.002" for bearings. Set valve tappets at 0.002" over factory specs.
Camshafts:
I have found the stock camshaft to be adequate and the ones used between 1957 and 1959 are supposed to be the best. A mild street grind would probably help. Iskendarian and Howard Cams used to offer camshafts for these engines, and most cam grinders have performance specs in their files.
Spark:
Use a 1951 or later distributor. Try to get a vacuum-advance unit which has a removable plug,allowing an adjustment of the amount of tension against the diaphragm. Road testing and adjustment will eliminate pre-ignition. Quality of fuel, humidity and altitude as well as compression and driving habits all enter into this adjustment. It’s another cut-and-try operation, but worth every minute spent. Four degrees initial advance to 36 degrees total works for a 251 ci engine that a friend runs in his 1958 Dodge coupe.
I used to love to watch a B-modified circle track racer powered by a 1954 Chrysler six beat the ohv competition. I have always admired the spirit of someone who dares to be different, especially if he’s a winner.
At this present time, I am running a 1957 Canadian Plymouth engine; originally a 215, it now displaces 260 ci due to a 3 7/16" plus a 0.060" overbore. It has been ported and polished, but runs stock carburetion and exhaust. Performance and mileage are impressive, and the modified oiling system adds a degree of reliability.
So there it is, you don’t need a Hemi to keep up with traffic. Enjoy that Dodge L-6. Overhead valves are just a passing fad.

Written by David Pollock. Excerpted from Chapter 14 "L-6 Engine Rebuild"in Dodge Pickups: History and Restoration Guide 1918-1971.

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57plymouth
Posted 2004-10-19 6:34 PM (#15718 - in reply to #13373)
Subject: RE: souped-up flathead 6



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Here is what I did: and most parts came from Vintage Power Wagons

Balanced bottom end, Military Spec pistons, stellite valves, Isky 3/4 cam and spring set, gasket matched the block to the intake and exhaust manifolds, decked the block and milled the stock head, pertronix coil, accel wires. I have not yet changed over to a split exhaust / dual carb setup, but that may happen in a year or two. I have battled bad balancers for a while and if another one fails I am going to go to that 440 block sitting in the corner (BIG stroker = BIG fun). With some careful tuning and several sets of points until I found a really great set, plus a set of very hot Autolite plugs (do they make anything else?) which took trying four sets until I was happy, I think I am making moderate power. It is NOT a hot rod, it will not bark the tires, it will not pin you in the seat, but after having driven this car for 14 years, it DID make a difference.
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59savoy
Posted 2004-10-25 10:30 PM (#16240 - in reply to #13373)
Subject: RE: souped-up flathead 6



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well, the post above got me very excited, but yours raises a question. having souped up a flathead, were you satisfied? going to a 440 is understandable under any circumstance, but did the six leave you a little (pardon the pun) flat? again, this car will be a driver, and i've definitely been known to follow a different drummer. on the other hand, i could drive a lawnmower and be different, which is not the plan. didja like the six? is there a mistake you made that i should avoid? what blew the balancer?
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62chrysler
Posted 2004-10-26 12:01 AM (#16275 - in reply to #13373)
Subject: RE: souped-up flathead 6



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If you really want to go crazy, go fuel injection
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DeSotohead
Posted 2004-10-26 8:51 AM (#16300 - in reply to #16275)
Subject: RE: souped-up flathead 6



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You can most likely splice in the hardware from something like a 4.0L Jeep or a 4.9L Dorf inline 6, and use either an ACCEL/DFI controller or maybe even roll your own from a GM application. Will have to make your own intake manifold, though.
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Bugman
Posted 2004-10-26 10:08 AM (#16302 - in reply to #16300)
Subject: RE: souped-up flathead 6



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Fuel injection conversions are easy. You can take any TBI 6 cylinder setup and just adapt the throttle body to your intake and mount the sensors and have Hypertech or Jet make you a chip for the computer. If you want REAL fuel injection, adapt a Hilborn setup. It won't be overly streetable, but you'll love the WOT power and the look.

Edited by Bugman 2004-10-26 10:09 AM
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57plymouth
Posted 2004-10-26 1:51 PM (#16309 - in reply to #13373)
Subject: RE: souped-up flathead 6



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Fuel injection would be a huge waste of time due to the nature of a flathead. Since the fuel charge will still have to make several U turns, it is a waste.

The balancers on the 57 to 59 engines suck. They are also the only ones that will fit in the frame. I ended up welding one solid. As for power, yes, it feels stronger, but a mild 318 would kick it's butt. Basically, the only reason I rebuilt the flattie was the fact that this car has been in my family since new, it was my first car, and it has the original engine. If the engine had been replaced or it was not original to my family, I would have yanked it. I am happy with the engine. It was not cheaper than building a V-8 for the car, nor is it fast at all. It is unusual, it get attention at car shows, and it is reliable as an anvil.
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59savoy
Posted 2004-10-31 9:15 PM (#16894 - in reply to #16309)
Subject: RE: souped-up flathead 6



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57plymouth - 2004-10-26 12:51 PM

Fuel injection would be a huge waste of time due to the nature of a flathead. Since the fuel charge will still have to make several U turns, it is a waste.

The balancers on the 57 to 59 engines suck. They are also the only ones that will fit in the frame. I ended up welding one solid. As for power, yes, it feels stronger, but a mild 318 would kick it's butt. Basically, the only reason I rebuilt the flattie was the fact that this car has been in my family since new, it was my first car, and it has the original engine. If the engine had been replaced or it was not original to my family, I would have yanked it. I am happy with the engine. It was not cheaper than building a V-8 for the car, nor is it fast at all. It is unusual, it get attention at car shows, and it is reliable as an anvil.


so what configuration did you go with? dual intake? fuelie? blower? is it worth the time to soup it up, or is a stock rebuild adequate?

i'm guessing the original flatty six was a reliable dog, and that it can be coaxed into being respectably reliable. am i correct? i'm not counting on burning serious rubber on a vehicle of this size and weight with a six banger. can you pass another car going down the highway on a two-lane? that's the real test for me.
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57plymouth
Posted 2004-11-01 7:52 AM (#16919 - in reply to #13373)
Subject: RE: souped-up flathead 6



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I used the stock intake and carb. I wanted the engine to look stone stock from the outside, because it basically is. It is as reliable as an anvil. When I took the motor apart, there was an inch of sand in the oil pan, the timing chain had 3/4 of an inch of slack, and both distributor weight springs were stretched to the point that I had full advance at idle. Now that it is rebuilt, it runs so cool that it uses only 1/4 of the temp. guage, it idles smooth as silk, and it uses no oil. I have the stock Powerflite tranny and rear axle. I am using 205/75/14 tires, which are the same size as the stockers. Top speed is about 70-75. It is not fast. It never will be with the flathead. I usually drive it about 60-65 on the interstate.
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