Lets Talk Mopar Flathead 6's...

Lets talk about these babies. I want to become educated on them; like HP, tranny swaps, speed parts and availability. Bearing types, suppliers and such.

Since the Ford Flatty 6 is producing a long thread of info, lets get this one going.

Who wants to lead off. I know Blueskies has a NICE flathead 6....

Who is running them and what do you got!

 

mine is a bone stock 217 w/ a three on the tree. but langdon's stovebolts started selling cast iron headers and i have seen some offy intakes, and a couple different heads.

www.stoveboltengineco.com

L

 

I'm running a 49 dodge flatty 6, Here in Oz our GM's are known as holdens, There a heaps of performance manifolds for twins, tripples, side drafts etc. Around mid 70's manifolds fit with minor mods, I will have a set of tripple webbers to get regesterd and when I get sick of that I'm mounting a blower to the sucker.

 

got a 51 218, moose from here made me a SWEET 2 pot intake with split headers, which i run down through 2 smithys.... 2 1/2" all the way, sounds KILLER... rest is stock except looks... EDGY still makes finned heads ($650 last i knew, and about a 6 week wait)... cams are made... i have a 3 on the tree... with a different flywheel 727 trans will hook right up... volaire rear ends are the only bolt up option... ummm.... canada got the best flatty mopar six in the trucks as the 250... i believe there was a short lived 265 for big stuff.... they can be NICE motors, i have NO complaints, nevre a break down, nothing... when i build a rod,i might just toss one in there too...

 

I yanked the 230ci six and 2spd pushbutton out of my '57 Plymouth last week. I even offered it up for free in the Classifieds, but didn't get much response.

 

I've got a freshly rebuilt 6 original to my 1940 business coupe. nothing done to it...yet. will probably get an intake from moose in the near future (thanks for the price quote moose). before i do that i'm trying to run down the pair of carbs i want to run. i'm undecided on exhaust. I'm also planning on a cam regrind...nothing to wild...just a little bumpy, but i need to source a spare i don't want to mess with the one original to the motor.

to you six gurus, will i be able to reliably cruise the interstate at around 70mph when all is said and done. i've done some searching on R.A.M.B. and other forums and i can't seem to pin down a good answer. i'm asking because as soon as i "get "er done", i'm planning to drive it almost daily (maybe a break during winter months). I commute about 15 miles to work every day. Why build it if you don't drive it.

 

The '59(and possibly '58) 230 head is the best performing factory head. It's slightly offset to the valve side of the block so the valves have less shrouding around them.

By all reports, they respond very well to some increased compression, and really really well to forced induction.

Crankshafts should be cross drilled between every journal for better oiling to the rods in performance oriented motors.

I discovered an easy way to get the cam and lifters out without pulling the head and valves. I'll post more on that with a pic later.

I also know that '55 and up timing sets are super expensive. Anyone know of anything cheaper that can be adapted?

 

I talked to a guy today...his name is George Asche, back east somewhere...a wizard on Plym, dodge, chrysler flathead sixes. He makes intakes, exhaust manifolds and rebuilds the OD setups too...seem sto be reasonable and knows alot of "shortcuts" to making the sixes HP for less money. I only have his number...814-354-2621. The guy does it all himself and everything is "Home made"

Im doing alot of research on these motors and will post my findings as I go.

Oh, as for the cruising speeds at 70...ask him, he would have the answer too.

Here is a link to a bunch of Mopar stuff - MOPAR LINKS

 

70mph with OD trans, no prob... with 3 on tree... i think its cool around 65 or so, above that and you rev the motor pretty bad... could always oversize tires a little bit to help out gear ratios... idk... i would say 65 is plenty doable though, and most people understand a cruizer in the right lane on the HWY... so no biggie to me.. with my setup, i can do about 60mph, or alteast thats as fast as ive had it on my 40 year old bias plys... on radials, 75 easy in my car... with no overdrive... im only at about 2500-2700 rpm at 60mph... got up around 65 once or twice, but limits here are 55 anyways, and i dont hit freeway that often, thats why i have my falcon, LOL..

 

Stock Flat 6 in my '40 Chrysler, would like to soup it up a bit, but it runs so perfectly the way it is, it would be a crime to tinker with it. Rod and Custom ran a car (I believe a '51 Plymouth, it's probably on their website) with a hot flathead six and the next month they got a TON of letters writing in about how cool it was to see the car running that motor. My Chrysler can do comfortable 55, maybe 60, but would need an OD to go much faster.

These engines will never be super fast, but they will always draw a crowd, hard to get attention with a small block V8, be it 350, 305, or 318. Long live the flathead.

 

Here's my '50 Plymouth 230 again, just in case you'd missed it previously-





You can read through the list of suppliers I used for my engine on my site, click the link in my signature. There's sound clips there too, of the engine with open headers no pipes, and with a pair of smithy mufflers. It sounds great...

I've only just started to drive my car in the last couple of weeks. I've put about 200 miles on it, and I still can't get over how well it runs. The Holley-Webber carbs are right out of the box, with only a simple mixture screw adjustment. The engine fires on the first stroke, and puuurrrrrrs. It accelerates nicely even in 3rd over, no sweat.

I drove the car to work today (40 miles roundtrip), and now that my overdrive is working, it cruizes down the road effortlessly. Keeps up with traffic like any other car. The overdrive makes it so much easier to drive, and with the 33% gear reduction, the engine rpm, less fuel consumption, road noise, etc are all vastly better than without od. I don't have a tach or speedo yet, so I don't have exact numbers, but the OD is worth the effort and price.

There's lots of stuff for these engines out there, with a little sluething and patience, and of course, cash.

I'd be happy to answer questions about my setup, drop me a line.

Pete

 

For running freeway speeds the two biggest issues are:

1.Gearing- you'll want the overdrive or a rear with 3.73 or (numerically) a bit lower (ie a higher gear...) The overdrives tend to be expensive and/or hard to find. If you go the rear end route, try to get something with an E-brake, because the stock ebrake is pretty worthless.

2. Brakes- OK, so it is not an engine related issue, but if you are running stock 10" Mopar drums 70mph feels pretty fast.

Here's mineforgive me for posting this same pic again): 218 balanced, Edmunds water heated dual intake, Carter B&B carbs reworked by George Asche, Custom tube headers from Phillips Exhaust in Oregon, Edmunds aluminum head, Stilko(!) oil filter. I've got an overdrive with the 4:11 rear, and power assisted, modern dual master cyl brakes with drilled drums.

 

55 Dodge "big truck" 265 six. 3-7/16 X 4-3/4. Balanced. Truck cam. Wide clearances on the tappets.

Shaved head. Factory dual exhaust and twin Carters.

Accel 300 + with a stock distributor. Twin oil filters and a pre-luber.

4.80 gears in the rear with a '54 Plymouth 3 speed overdrive. Cruises at 80 with no problems.

Got about 50,000 miles or more on the engine since rebuilding it in '86.

 

This is Frankenstein, the heart is a '49 Chrysler Spitfire, C45 250. It's a fluid drive 3 spd that I re-routed to the floor. I know it won't scream, but it is different. I am in the process of bringing the beast to life. Moose is building a killer manifold that should give her a hotter breath!

"The Joy of Six"

 

BTW, while we're talking about these crazy mills, anyone know what I could use for a Tach? I decided to keep it 6 volt for now. I'm already regretting that, but money is tight, and I had all the parts for it.

 

How about the Hudson flathead six?

I remember in the 60's a guy running a 308 cube Hudson oval tracking.

 

4Woody-

Curious what kind of performance improvements you've noticed with the drilled drums. I'm thinking about having mine drill next winter, if I haven't decided to do a disc swap by then...

Pete

 

Ok 51ratt, which flywheel? I have a 904 and a 727 and 4 bell housings. one is off of a slant six, They all seem to bolt right up but I have not found a flywheel. Any help would be great. Oh yeah my flat 6

 

Pete-
It is a noticable improvement with regards to fade on downhills. What was once scary is now no problem. It's supposed to also help alot in the rain, but since the car is wood and not well sealed I try really hard never to be in rain in the first place.

If I had it all to do over again, I don't know. The cost to totally rebuild my brake system, turn the drums and have them drilled, new cylinders and shoes all around etc is pretty close to the cost of doing discs.

I will say I'm happy with the results the way I did it though.

 

I'm running my 51 plymouth with the original flatty in it. Plenty good for me, tho i do need to upgrade to the overdrive. Blueskies website is a great resource for the overdrive swap. Happy with the performance (no real grins tho). I do have a question. Lately I have had quite a bit of smoke coming through the oil breather cap. I'm not burning any oil, and it smells like exhaust. I'm not used to non pcv engines and was wondering what this might be caused by. I might make this its own thread cause the ford guys could have run into it before. Thanks for any help. OH... BTW it gets worse (more smoke) at higher rpms.

 

I've seen Mopar flathead distributors with mechanical tach output jack on ebay pretty regularly.

 

61linc-

Sounds like your engine has a blowby problem with the rings. The compression leaks past the rings, pressurizing the block. The down draft tube on the passenger side is supposed to create enough draw on the block to pull air in from the fill tube, clearing the vapors as you drive. Once the blowby gets bad enough, it will push the vapors out the fill tube, especially when the car is moving slowly or idling at a stand still. My engine was pretty bad, the fumes filled the car when I stopped at a light.

Here's what my engine looked like "before"... There was an oily film on everything under the hood from the blowby.



When I tore the engine down, I discovered that the top compression ring was broken on all six pistons, and two of them had the top ring pound through the top of the piston. The exhaust didn't smoke much, and it didn't burn much oil either. And it ran pretty good, or so I thought...

Here's a couple of piston pics for grins, my favorite shots of the rebuild- The top ring groove in the piston was worn big enough for two rings. You can see the bits of ring that had stacked together. The rest of the top ring on this piston wasn't there, it had apparently escaped through the hole in the edge of the piston and found a new home in the muffler.




This gives you a pretty good visual of the piston moving up and down at high rpm, doesn't it? And the ring moving the opposite direction...


When I pulled the pistons, the what was left of the top ring fell on the floor from all six.


Pete

 

Once again pete, you are a wealth of info on these plymouths. Mine does it in the opposite though, and is bad when driving it at high rpms. It does fill the cabin quite well, so I drive with my head out the window at times. How much were replacement pistons? I imagine I will need all six as well. thanks again.

 

I'm running a 49 Ply bizzy coupe with a 218 that has had the head milled .070. I am using an offy dual carb intake and have an OD tranny from a 53 plymouth...65 mph...no problem...70...I think I had better get my front end rebuilt....I am also building a street roadster with a chrysler flat 6 "spitfire" engine. I have it hooked to a 350 turbo through an adapter from WILCAP. It has an 8" rear end with 3.00 gears...running 31" tall tires I think i can do about 125 easy. The motor was built by George Asche....it's a 250 bored .040, chrome crank and a nice street cam. I have a vintage Edmunds dual intake with Rochester carbs...go to

www.msnusers.com/streetroadster

Wanted...Finned Aluminum Head for flat 6 chrysler

 

bigticket do you have any pics of the350 behind the flat six with the adapter.Do you use the flat six bellhousing or the 350 bellhousing ? Details please

 

Grinder, if you go to www.msnusers.com/streetroadster there will be pictures of the adapter and how it is mounted to the engine. You will notice you do not use the bellhousing from the flat 6. This was a very easy set up. Everything in the kit was top grade...Look up WILCAP on Google for the web address...ask for Pat McQuire...tell him I sent you....a really great guy...Hope this helps you out...regards. John Burke

 

G,day fellas guru here.I,ve got a few questions:I,m buildin a rat style pickup/60s show rod with a 56 dodge 230 donk,How do you time these buggers it doesn,t appear to have timin marx on tha balancer/dampner except 4 2 small 1/4" indents on tha dampner? Do these mean something! I,m to tha point of yankin tha side cover and turning tha motor over to watch 4 number 1 valves to open.Unfortunately I,m reluctant to do this 4 new gaskets are pricey and we,re broke tho ill make my own if i have 2. I also have a channelled 56/54 style dodge ute,GM/H chassis OldsV8 ,these predate your ranchero & El caminos.I also drive a 50s kustom daily as will the missus when her wagon is done. Thanx Fellas.

 

I've never actually timed my Flathead. I've always timed it by ear, and it seems to run pretty good.

 

i'm runnin the 218 flat 6 in my '52 plymouth. no mods besides the oil bath cleaner is replaced, and i am runnin a straight pipe! motor runs like a tank! although i could imagine my pistons look like blueskies did!! any info on those moose header, and intake combos would be appreciated. i want something better..and better to look at. -josh