Hot Rods Best breathing flathead 6

Strange ideas get in my head sometimes. Searched for this but I'm not really good with computers. Some of you may have figured that out by now from the updates on the whatever project thread. You can beat me arouse the ears figuratively if you want, I won't take it personally!

So I had this thought about flathead 6s. If one was to be modified a little bit, what one would make a decent choice? I would think that if there's one with 12 ports, that are short and not sharper than 90 degrees, that would breathe the best. And as an engine is nothing more than an air pump, and the more air flow through an engine the more power can be made, then the one with the best ports should be able to make the best power.

So I figured I'd ask for the collective wisdom of the hamb for thoughts on this subject. And like I said I can take it if snide comments need to be made...

Thanks

 

The Hudson has 12 ports and the valves are canted at an angle towards the cylinders. They also had fairly large valves.

 

A guy on here got 208hp out of a modified Plymouth 230 flathead six.

 

One with a supercharger will breathe well.

 

So thinking back to the early 60's and Joe Messina at Lebanon Valley, the Hudson engines he raced seemed to run good. Hmmm, ok that's the 1st I'll have to check out.

 

@Dave G in Gansevoort Im not positive but Im pretty sure we had some running in Middletown .

 

Chrysler flathead six's were pretty stout on alky with chevy pistons and the block and head milled.

 

I read somewhere that Holman Moody built some Ford I6 for boat racing in the early 50's. Don't know HP.

 

Holman and Moody was founded in 1957, it might of been Bill Stroppe that was running the Ford team before that on the West coast.

 

I seem to remember reading in old HR magazines about inline 6s in smaller race boats. That's another area to research. Thanks for kicking the little gray cells into gear...

 

I remember a guy running a chrysler flat six in a circle track car at the old watertown ny fairgrounds speedway, in the early 1960's. The thing was an ok runner against the V8's. The owner put Bob Zeigler in the seat one night( Zeigler was a pretty fair shoe at the time). The damn Mopar lead every lap of that feature that night and won going away. Point being ,a darn good motor even spotting the field 20 cubes. Probably didn't hurt that Zeigler is the all time winningest guy to ever run there, but that little inline sure did sing that night.

 

HAHAHAHAHAHAHAHHA (gasp) AHAHAA HAHAHAHAHAA (tears in eyes) HAHAHAHAHAHA ...
oh, you are serious

Isn't that like asking who is the tallest small person


Kindly disregard the above and carry on

 

Which flat six came first, Chrysler or Corvair??

 

Neither….it was the Hall-Scott……

Ray

 

Smokey Yunick got his start building Nascar Hudson Hornet flathead 6's in the early 1950's. Back then the cars and engines were actual production stock with a bit a cheating when possible...The 308 Hudson 6 with the special factory heavy duty parts and Yunick tuning made about 225 hp..

 

The Hudson in my opinion is your best bet. I do not have any empirical data to support my opinion so it is just opinion.

Other then the nostalgic value I think it is a total waste of time to build a flathead 6 by the way.

 

Yes! That's the answer, now what's the question?

 

Let's say that the effort would be to make something welcome at multiple venues. Same question, except open to ohv 6s.

 

Hey hey hey there now!! I love my little flat six!

 

Hudson, for the reasons already given.
A flathead can have as large and well shaped ports as an OHV from the carb to the intake valve seat, and from the exhaust valve seat out the headers.
It can also have a wider valve chamber than the cylinder, meaning larger valves.
The restriction is in the sharp turn from the valve area to the cylinder . And the narrowness of the transfer passage. The more open the head, the more room to breathe but the lower compression. This is the compromise that killed the flathead. When low octane gas limited compression to 7.5:1 or less the OHV had little or no performance advantage, and the flathead had several practical advantages like low cost, simplicity, silence, and it was immune to valve interference if you broke a valve spring in other words, the piston could not crash into the valve.
Example - two American luxury cars got new V8s in 1949. The Cadillac, everyone remembers, and the Lincoln everyone forgets. One OHV, one flathead. Both about the same size, 331 cu in and 337 cu in. Both with 7.5:1 compression. Cadillac 160HP Lincoln 154HP. So a very slight advantage to Cadillac.
But the Cadillac had to potential of up to 10:1 compression and 250HP which was realized a few years later. Lincoln dropped the flathead for a new OHV after only 3 years.

 

302 GMC and 300 Fords

 

The real answer to a performance flathead is a centrifugal supercharger as used by Graham and Auburn prewar and Kaiser afterwards. It makes up for the breathing restriction and the lower compression. Graham's blown six made the same HP as their unblown straight eight, and Auburn's blown eight made the same HP as their V12. Kaiser's blown six made the same HP as competitors' OHV V8s. None of these had more than 4 or 5 pounds of boost.

 

Chrysler built flathead six's all the way up to 413 ci. All the big motors had 7 mains, nickle steel blocks and 12 ports.

Yeah, the first Mopar 413 was a flathead, not a V8 ...

 

A 4.3 Chevy was a 350 with 2 cylinders chopped off. So that makes it a traditional small block missing 2 cylinders. All the accessories directly bolt on. Has 6 separate intake ports and 6 separate exhaust ports. Can be fitted with bigger valves, supercharger or turbocharger easily. And there is even headers available for them. Oh and it’s a 301!
So tell me Chuck what did I win? I hope a new old car!

 

Since when is a 4.3 Chevy a flathead?

 

Since the 302 GMC and FORD 300 became flatheads I guess... BTW, my Uncle had a Gray Marine flat six in his old Century boat, big inch with multiple carbs. He really liked that engine, used to say how sweet it sounded and how well it scooted that hull across the water. I dont know much about them except for his storys. Mitch

 

LOL!

Ben

 

Were the "Grey Marine" engines their own deal or maybe re-labeled Chrysler flatheads? (Those came in 251 and 265 ci varieties.) I remember back in the sixties on Lake Minnetonka, there were a bunch of Chris-Craft's and Century's running those engines. As I remember it, they all had multiple carbs, and if in decent shape, ran strong.

That being said, my vote is for the 308 Hudson.

 

Tub, I believe Gray Marine had their own engines gas and diesel. Not the thing to put in a Hot Rod though, unless it was one of those R_ _ R_ _ things I suppose.

 

The old Gray Marine flatheads I saw were indeed Chrysler engines with dual updraft carburetors.