Technical Powerband / Peak Torque Chrysler Flathead 6

You're gonna need a 3.90 or 4.10 gear if that thing spins north of 5000 rpm... and tube headers to boot! Your torque peak will be moved way up there with a cam like that.

 

Yea I do, not sure what it came out of . The shift mechanism was somewhat unique. I didn't use any of it, the original truck linkage and shift arms bolted right on in its place.

 

Well you never can tell, and spinning up to 5 grand is not what my everyday driving will be about anyways..
Have a look at these,
https://www.youtube.com/watch?time_continue=7&v=DVsGYDcWUPI

 

And most likely the wickedest Chrysler flathead on the planet,

 

I think you need to try somebody else other than the AOK boys for info.
There are other guys with a lot of flathead time and secrets, and for whatever reason what they do is pretty weird from any sort of modern performance standpoint.

 

I think we will "agree to disagree", yes there are other knowledgeable Mopar Flathead people, just never met any with a long term proven track record like the AoK Boys....

 

That '33 race car sounds good...

 

Okay Mr DR, after a day or so, you have peaked my curiosity.
I would like to know how you would approach my engine and plan.
The engine a 1960s Chrysler Industrial 265, nothing has been done to it to date, no head milling or cam grind.
How would you approach this build for the street for max power and reliability?

 

I would have a real close look at what is in it first.
But a good dual carb intake, with some modern 1bbl carbs.
A tube header. Split banks front and back.longest runners I could package. Same diameter as the ports or a very small amount bigger.
Grind the casting flash out of the ports.
8.5:1 compression not more than that.
Chrysler crown marine cam .404 intake,.378 exhaust. (Unless the industrial cam is better, but watch the lobe sep. they can be ground for stationary power and will only make power at one specific rpm)
Grooved main bearings.
At least 50 psi oil pressure and blueprint the pump.
Maybe a balance job.
Ya wanna get real trick look at unshrouding the valves and milling the head to Harley flathead design.

That would be the quick and easy version.

 

Carbs- I have professionally built Carter Ball & Ball large bore /venture/cfm matched truck carbs they are great, don't see a need for another type
-headers, do not see the need for a cruiser street application, and the longest runners for this engine are not necessarily the best idea. Some headers are great but not the Fenton repops from Langdons, the design is way wrong.
-relieving the ports on the flathead 6, nah that's a Ford flathead V8 idea, not a great idea for this engine
-well without going to an aftermarket head like an Edmunds, shaving a stock head will not get you much more than 8:1 unless you enjoy swapping head gaskets for fun.
-Chrysler Crown engine, that grind is way wrong for the street driven car or truck, it's really designed for idling and WOT, a more lift and duration is a must for RPM and more power, but the boat cam not sure about that one
- grooved main bearing and other tricks are great ideas, and would be something really necessary for revving up north of 5000 grand or so, under 5200 not needed.
-well my stock oil pump on the old 228 has 40 psi at idle and near 55-60 while cruising, a good high volume oil pump can do the job, blue printing an oil pump is most likely a Chevy engine thing.
- engine balancing of the rotating parts, well the crank is forged and well balanced stock, the rods and pistons are a good idea to balance for a build did you know Chrysler flathead 6s cranks are forged and factory balanced?
Shrouding, this is a real issue with Furd flathead V8s and not an issue with this engine, what gives you this idea?
So to sum things up, what are you doing for your engine build or what have you planned, is this for your Ford Truck?

 

Yes this mostly what I am doing on my 201 but I am planning on putting the crank and rods out of a 230 in it.
The ball and ball carbs are poor at best. I have a set, all rebuilt and ready to go. Problem is they don't have a very good nozzle design. I have had very good luck with autolite 1100's. Remember that flatheads don't run multiple carbs for cfm but to get the fuel into the cylinders. As your vacum signal drops from multiple carbs this problem gets worse.

The grooves in the main bearings are too small, period. They don't feed enough oil to the rods. Look at the size of the hole in the crank, then the groove in the main bearing. Do a little math and realize you have a pressure drop due to that restriction.
Blueprinting an oil pump is relatively easy. And can make a huge difference in oil delivery with out a change in pressure. I have done dozens of helicopter oil pumps. At only about 50 psi volume is key. It can make a massive difference.

Headers are a no brainer. Google exhaust reversion. I built a shorty tri y design on the dodge. It pushed the torque curve up in the rpm range which was less than ideal but still made a significant increase in power.
The ports on a dodge/ply flathead are pretty good. But a clean up and shape check with a set of spring calipers can't hurt. Google exhaust scavenging.

I have never built a Chevy engine(why would I?) but have spent decades fooling with everything from tractors, race sleds to CT58 GE gas turbine engines. There are things that build reliability and power and things that should have been left in the scrap pile 40 years ago.

I am not arguing with you, I am also not trying to sell you anything. I like the flathead six, and some of the things you read and are told are old wives tales.

 

the install of the 230 crank is going to be quite invasive to the base metal of the block or the crank and if thinking possibly shared between a line bore of the block journals and the under-cutting of the crank. Bearings will become an issue here more than not...study....studyose prior to any n on return cut.


QUOTE="dumprat, post: 12264165, member: 24850"]Yes this mostly what I am doing on my 201 but I am planning on putting the crank and rods out of a 230 in it.
The ball and ball carbs are poor at best. I have a set, all rebuilt and ready to go. Problem is they don't have a very good nozzle design. I have had very good luck with autolite 1100's. Remember that flatheads don't run multiple carbs for cfm but to get the fuel into the cylinders. As your vacum signal drops from multiple carbs this problem gets worse.QUOTE]

 

The mains are supposed to be the same size according to the literature.

 

the 201 has a journal of 2.249-2.250 while the 218/230 has a 2.499-2.500 so you can see there is a .250 difference, they do share the same stroke (201/218) but again the rod journals are .013 larger on the 218/230 while the stroke is longer on the 230

 

I'm building a Chrysler 265 now with a .030 bore new pistons rings and bearings, valves, with cam regrind to 400 junior specs-405 lift , 230 duration at .50 , manifolds by moose with 3 Weber 32/36 progressive carbs, head shaved .085 , hei ignition by langdons backed by an R10 overdrive trans and 3.90 rear in a 40 Plymouth Club Coupe 2,800 lb. car. edgy 25" head on order from Montana Dodge Boys.

 

"Ask the man who owns one" in this case the original owner of a 1951 DeSoto Suburban eight passenger sedan who drove it over 175,000 miles. I will let him explain in detail his experiences in driving this car from Death Valley to the top of the Rocky Mountains, towing a trailer.

He says "Operation above 3600 RPM is avoided in the interest of long engine life, especially with such a long stroke. But continuous full throttle operation on upgrades at 3200 presents no problems."

My favorite part " at high altitude at 70MPH the engine smooths out like a perfectly balanced turbine". This in a 6000 pound car with flathead six and 4:11 gears :0

https://www.allpar.com/cars/desoto/suburban-1951.html

 

Kool, what did your 265 come out of?
Your waiting on an Edgy head, now being cast by Edelbrock but under license from Edgy.
I would go with a higher lift cam with all that induction possibly...

 

Think you'll really like the improvement with performance and drivability. The overdrive is the key. My motor runs about 1800 at 65mph and the engine responded to the card/intake/exhaust/head..

 

How do you find it is at 60 to 70 mph in overdrive?
Thats like 1650 rpm at 60 mph? Any engine lugging?
Now if your cam duration is not too long then your torque will be lower in tbe powerband?

 

My motor is smaller than what your building I have a 218 bored .040 but compared to stock it is a world of difference
The acceleration from 0 to 55 allows you to run with traffic and
Easily cruise at 75 and actually pass vehicles. The carbs really improved drivability. I drove this wagon for about 1 year before doing the motor. It's now a pleasure to drive

 

Kool do you use overdrive at 60 mph?
So you cruise a lot at 75 mph?
Im.just trying to figure out how you are running in overdrive at kind of a low RPM and not lugging.
Yah these are great little engines..

 

The overdrive unit has a governor that control engagement . You must be doing 35/40 and above for overdrive unit to engage and you control its engagement with throttle pedal . As long as you're accelerating or keep light throttle pressure on it will not engage. Crack the throttle and allow the the torque from engine to relax the drivetrain it engage. As you slow down and the vehicle slows to below 40 the governor turns off the overdrive. You also have a manual pull cable to either turn off the unit or allow it to operate. There Borg Warner unit like every one used. There's a few side switches for passing gear but you get the idea. It's the best option you can have. At 75 I'm about 2000 rpm(with my tach) drive it to Atlanta. 20 mpg
Using the wagon on the hot rod power tour this year

 

Hey Rich, what rear gears are you planning on running with?
Im getting a 265 rebuilt and plan on using a T5 transmission behind it


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Oopss. Just read your entire post ‍♂️. 3.90


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The picture of the R-10 overdrive shows most of a floor shift conversion that was briefly available in the late 1950's. It worked OK if you did not mind the odd shift patern which was backward and forward and you pushed down and held for first and reverse. There are better one's available but they have more parts and hence more expensive.