I have an inline 6 from a 1951 or 52 Dodge Coronet that needs some attention. Stock it weighs in @ just over 100hp and the torque numbers aren't exactly flattering either. I just found out the compression numbers.....7.0, no wonder the numbers are so low. I am not looking for 500+ hp or anything that will propel this car to 200mph. I would just like to feel a little safer pulling out into traffic and not have to downshift on some of the hills I drive. I have located a machine shop to do some porting and polishing and the other major block work; what I haven't found is a plethora of power options for this engine. I have put a lot of thought into my engine and transmission options and this is the route I want to take. I do live in Cullman, AL, so that will limit my options as to where I can go to get work done. Atlanta, Nashville, Birmingham are all within the realm of possibilities If I could get somewhere near 160-190 hp and closer to 300ft/lb of torque that would be fantastic.
I will open by saying I don't know much about Mopars but when I was a kid I had a Dodge with a flathead 6, saying it was underpowered would be an understatement! A good friend of my Dad's suggested putting in a Chrysler motor that he had laying around, I think it was a 251(?). It was slightly longer than the Dodge motor but it seems to me it bolted right in. What a difference that made to that old Dodge it pulled like a mule and would highway cruise at 65-70 all day long. There was a time when there were lots of them around, but I would try to find one of those as a base for a stock appearing motor.
Good luck on the 160 hp. I have a 48 P-15 plymouth with a 41 Dodge 6 that I rebuilt. I ended up with over $2500.00 in the engine with the dual intake manifold and new parts and machine work. You can use Chevrolet stainless steel exhaust valves from the 350. The valves come in two sizes which are a little larger than the original valves. The block already has hardened exhaust valve seats from the factory so you can save some money there. It is hard to find a machine shop that is knowable about the old MoPar flat head engines. There is a plug in the center of the combustion chamber of number 6 cylinder used to measure stroke and to find TDC, make the machine shop aware that that is not a flaw in the head casting on the combustion side of the head. It is hard to increase the lift on the cam as there is very little heal to remove to increase the lift. About all you can archive on the cam is more duration which helps. You need to go to the P15/D24 forum and look at their home page to find a list of vendors that supply parts. This site if for all flat head Chrysler produced engines and cars, you will be welcomed if you decide to post their. Someone there will be able to answer your questions about engine modifications and transmission choices. Pete Anderson AKA "Blueskies" who used to post here and on the P15/D24 forum built the ultimate flat head Plymouth engine, it has inspired many a person. Search here for his name and maybe you can find his old site where he posted all of his pictures.
150 no not reliably. 135 140 no problem, shave the head, deck the block, do a mild cam, you want to keep you power and torque rating in the low to mid rpm range. add a 2bbl or a pair of stock singles on a vintage dual intake or a split stock intake, gasket match the ports, and add a less restrictive exhaust system. You are dealing with a long stroke engine (4 5/8") they don't like high reves because piston travel friction negates any power they might try make about 3800 Rpm. Can you do it for a racing engine, maybe for a street motor why??? I have a 56 230 in my plymouth coupe that puts 127 HP to the rear wheels on the chassis dyno, keeps up with traffic, climbs hill, and cruises all day at 60 at 18 to 19 mpg. This will dual carbs, single exhaust, stock cam, and .010 off the block, and .050 off the head. (cr is now about 8.5 to 1 ) If you build more than that you need to cross drill the crank for better oiling. A good balancing and shaving some weight off the flywheel are worth donig also. Contact member Olddaddy at rustyhope.com for split manifolds, or contac member Moose for some wilder intake and exhaust options.
there are actually quite a few hopped up Mopar flathead sixes here on the HAMB. I documented one a few years ago. To get up with modern traffic--- a properly tuned dual carb, and dual exhaust increase compression. Mill the head. port work and bigger valves are all fine and dandy, but these engines have other obstacles to power, efficiency and longevity that could yield better "bang for the buck" if addressed as with anything, how much time and money do you have?
Time....I hope I have another 45 years in me. Money......I am going to dump a whole lot more into this than I should. The money is fixed monthly, so I have time to budget what I want to do. I am very interested in the dual carb set up. I guess I need to start looking for a set up that is complete. 8.5 to 1 sounds lovely compared to what I have been driving. I was being hopefully optimistic on 160. One can always keep their head in the clouds as long as their feet stay planted firmly on the ground. 127 does sound so much better than 103. Keep the comments coming. I have been adding little bits here and there to this build and hopefully once the pile of parts gets big enough, I'll have enough energy to put it all back together.
That engine was used in forklifts and other industrial machinery for years after it disappeared from auto/truck lines. This means great parts availability.
dont relieve the block around the valves like you would on a ford- not needed and would only lower compression more. For mine,I'm thinking doing some durability upgrades and then a REASONABLE amount of boost from a small blower/turbo rick
I had thought about a small turbo from a 2.0L car and the low compression, but don't know if I really want to put that much energy into dialing it in.
I was gonna suggest turbo, but seeing how it is non-traditional... But, since you brought it up.... A Garrett T3 from any of the 80's or 90's 4 banger turbo cars would work great; dodge daytona, mitsubitshi, t-bird. The easiest setup is a fabricated manifold with 350cfm Holley carb in a blowthrough configuration. You'll need rising rate FPR and EFI fuel pump, boost timing retard of some sort, and a little patience tuning. Start out around 4psi and tinker your way up. I have done three custom turbo gasser projects so if you decided to go that route I'd be glad to help.
I'm in the same boat, I have a '47 Dodge with a 230. I've already gotten the dual carb intake, going to be pulling the motor soon to have some of the machine work done that was already mentioned. I'm looking for around 120 but I have a fluid drive I plan on keeping so it will be less noticeable than a standard tranny car.
I may take you up on that. I have a guy that can do the work/help me with the work. The biggest problem with the Turbo for me......is proper cooling and making sure I don't melt down a newly rebuilt engine. Boost gauge is a definite must.
Boost, EGT and AFR guages are kindof a must. It is a little costly, but you just have to have it to tune a street engine. The last one I did was a 1949 M Farmall. I had it setup like I outlined with a little T3 and it worked great at 12-15psi and 2500RPM.......then I decided to go crazy with it and went to a big turbo/high RPM setup. It made 24psi boost at 4300RPM blowing through a 500 cfm Holley with two stage water injection. It was a beast, but kept coming apart....guess 10x the factory rated HP tends to do that. The thing you have to do to keep them together is stay conservative. You can pretty easily double factory HP and keep it safe. I would love to help with another build. It has been about 5 years.
Are you dead set on using the six? sounds like using 2.5L and a 5 speed from pickup would meet your needs just fine and get you around 24mpg. got one in my OT daily and I can cruse at or above highway speeds with little effort. That being said this sounds like a interesting project
Dynaflash_8 on here is a younger guy, but has played around with some BAD mopar flatties. Myself i'd rig up a small blower to overcome the inherint L-head breating charecteristics
I just picked up a garrett T3 for a turbo 230 build. Plan to start on it sometime next year. You can build these motors just like any other, but they become a pain real quick. Here was my old 218 made into a 230. cam was .480 lift, and comp was 9.0 to 1. dual carb manifold modded to fit 2 holly singles at 115cfm each, cast manifolds, lots of port work and fully balenced. <iframe width="480" height="390" src="http://www.youtube.com/embed/2GvypCT64ww" frameborder="0" allowfullscreen></iframe>
these flatheads were designed as low-revvers that depended on being matched to low gear ratios that maximized torque. It's almost like trying to hot-rod a diesel motor. This is one of the characteristics that has drawn me to want to build a daily driver using a 130hp flathead with a modern OD transmission & 3.55:1 axle. I've read some folks try to squeeze more hp out of these blocks, but there's a breakover point to how much $$$ spent compared to how much hp generated. The easiest mod combination seems to be shaving the head to boost CR to 8:1, 2bbl carb, and split exhaust manifold.
Pretty cool, Dyna. Turbos at low boost are a real easy way to raise useable power and there is very little added stress because you can do it at lower RPM. You just have to keep it reasonable which is hard once you find out how well they work. It is so easy to turn up the wick.....
I like the fluid drive transmission. It is always a conversation piece with the younger crowd. Having the odd 3 speed on the column is fun too.
least on the power adder.I am still open for suggestions. I found a car to pull turbo parts from, just looking into all available options. I like traditional, but may go new school on the motor, at least on the power adder.
I don't remember what motor this was - pretty sure it was dodge or desoto . . . purported to get down the quarter mile in the 12 second or better range. A motor is nothing more than a pump - make it breath and you can make power. compression, cam, valves, induction, exhaust . . .
Check out the P15-D24 site http://www430.pair.com/p15d24/mopar_...eferrerid=1152 your car mechanically is essentially the same car as the 46-48's You can also look at Edgy Speed Shop for finned aluminum head, intake and reground cams http://edgyspeedshop.com/ Langdon's Stovebolt Engine Co for intake, cast iron headers and HEI distributor http://stoveboltengineco.com/ Paul Curtis for an adaptor to mount a T5 5 speed behind the flathead https://home.comcast.net/~pjplymouth/t5.html Blueskies site http://www.50plymouth.com/04-eng/eng.html Other Threads to look through http://www.jalopyjournal.com/forum/showthread.php?t=604008&highlight=edgy http://www.jalopyjournal.com/forum/showthread.php?t=429644 http://www.jalopyjournal.com/forum/showthread.php?t=588805&highlight=plymouth+flathead http://www.jalopyjournal.com/forum/showthread.php?t=315555&highlight=plymouth+flathead http://www.jalopyjournal.com/forum/showthread.php?t=446905&highlight=plymouth+flathead <!-- / message -->
Don't believe it is MOPAR as they have siamesed intake ports, Maybe a Hudson, they are a beast of another stripe. If you are building for the street I believe you want relability, more than ultimate power output. Most folks over cam and over carb and then end up with a vehicle that isn't good for much of anything. If you stick with the knowns of these engines you will have a good driving car that will do well in traffic, run dependably, and get decent fuel mileage. Compression: you can go .090 off (assuming stuff is stock) and its good to take some off the deck as well as the head .010 off the block and .060 off the head will give you about 9 to 1 CR. Any more will require premium gas and will stress the lower end. Carbs: Dual stock carters, or dual pinto carter webers, or a single 2bbl (was an option in 56) are good fo 8 to 12 HP Cam: stock works good, a little extra duration can't hurt, but a bunch of lift is not necessary Flywheel: lightening with a dry clutch 3 speed is worth while, with fluid drive it's not necessary or helpful Ignition, stock is good, pertronix makes a kit for chrysler industrial and agricultural applications that works. 6V positive is available. You can buy a electronic deal from Stovebolt based on GM stuff, but then you need to convert to 12V. The other option is priating and modifying MOPAR /6 electronic ign. You need to modify the /6 dist by swaping out the drive tang and slightly machining the bottom to fit the flatie block. Exhaust: Go 2 inch Id all the way or get a split exhaust. ( along with increased compression probably the best bag for the buck) Port matching: To the gaskets, knock your self out if you want to but not really necessary. Anything more is pushig the envelope and will give you more problems than HP. As stated before, you want to do what ever will help your engine work between 2000, and 3400 rpm. And start by asking if ford needed 8 cylinders to make 85 or 100 HP, how Walter P could make 97 HP to 132 HP with 6?? If you want more than you can make with the 6, then your answer lies with a swap, not in a radical 6 build. As for pressurizing the intake, Graham Paige, used a centrifugal super charger in the 30's and 40's on their 218 cu in 6. the normally aspirated engine made 95 HP the blown one made 125. in the mid 50's Kaiser used a paxton supercharger on their 226 inch cotinental engine to go from 122 HP to 140. Some of us have talked about using the early MOPAR 4 cyl turbo hardware on a flattie. Sourced from the Turbo shelby GLH or the Chrysler K car. these were pretty simple used a throttle body fuel injector and were limited to about 10 lbs of boost. they had a simple electronic control circuit and a compact turbo, and increased HP by about 25 or 30. But a switch to 12V would be necessary and a couple 02 sensors would need to go in also. Somewhere on the web there is a site put together by a fellow who turboed a flat 6 Studebaker. All that info and all the problems should transfer over to the mopar. If I were starting out to build the car, I would make it run, drive and stop, then look at compression first, exhaust 2nd, intake third, then ignition. I believe you can get an new Offy dual single intake from Summit racing ( not in the catalog but call) for inthe 300 buck neighborhood. Day dreams and pie in the sky is a cool mental excercise but it won't build a reliable street engine. (Ask Dynaflash 8)
The Jalopy Journal
