[fomoco56]

Hello, I love the sounds of old Ford Flatheads, What has anyone ever done to improve porting of the Exhaust ports from the valve seat all the way down thru the block to get the engine to breath better, not just an inch or so from the exhaust manifold ? I see where in the past putting a partition betreew the center two cylinders, that is not enough to make it breath.
Thanks for any answers

[techinspector1]

Only way I know of to get max dependable power out of a flathead is to bolt a blower on it. Naturally aspirated, the coolest setup I have seen is to rig up a blower to puff through the exhaust ports and taking the exhaust out of the top where the intake runners are.

[DanielC]

It is not just the exhaust that limits the breathing on a Flathead. It is the whole arrangement of the engine. Think of all the turns the gases have to make to get into the cylinders.

[oldbogie]

Originally Posted by fomoco56

Hello, I love the sounds of old Ford Flatheads, What has anyone ever done to improve porting of the Exhaust ports from the valve seat all the way down thru the block to get the engine to breath better, not just an inch or so from the exhaust manifold ? I see where in the past putting a partition betreew the center two cylinders, that is not enough to make it breath.
Thanks for any answers

There are two good reasons why the flathead was superseded by the overhead. They are breathing and combustion.

The flathead combustion chamber is large making the burn slow and the compression low. Efforts to fix these problems, especially compression always lead to breathing restrictions between the valve and the cylinder. So like a dog chasing its tail, fixing one creates a problem with the other.

The other problem is breathing to and from the valve, the path is tortuous. In the good old days the intake solution was to make them as big and shiny as possible. Shiny wasn't required but it looks good. Given the limits of the combustion chamber and spark plug location there aren't any games to be played with developing swirl and wet flow into the combustion chamber.

The exhaust's biggest problem isn't the Siamesed center cylinder outlet so much as the amount of exhaust port exposed inside the cooling jacket. The double whammy here is the exhaust gives up a lot of heat to the cooling system making these installations easy to overheat while reducing high velocity flow in the port by cooling thus contracting the exhaust gasses before they can be put to work pulling in fresh charge during the cam's overlap phase. given this isn't going to be a high RPM motor for a lot of engineering reasons, the exhaust is best kept small and use a good header. Separating the Siamesed port to individual cylinders would help but that port isn't large enough to start with so a divider only makes it smaller, this drives you to port the passage dangerously thin to get the needed area. While this allows adequate life for a race engine, at least back when blocks were plentiful, it just is a major failure point for a street engine that's expected to last into 10s of thousands of miles.

The flathead makes a very nice period correct engine, but to get any kind of power out of it takes a blower, back in their heyday there were gobs of people making blowers for these things. A blower at least forces a solution to the intake side porting and valve inadequacies and helps put a lot of much needed agitation into the combustion chamber. But output is limited by the exhaust porting which just makes all the existing issues I sighted that much worse when a blower is bolted on.

This isn't to say that building and using a flathead isn't a lot of fun, but they have their limitations that in the end even the OEMs couldn't overcome.

Bogie

[Irelands child]

Then there is the Ardun OHV conversion PLUS a blower and ADD the crossfire mod - best of all worlds, but you need to be a signatory to Fort Knox's gold supply to afford any or parts of that arrangement these days

[timothale]

I had a friend that was partners in a 27 T altered running ardun heads and a Scott blower // they set a few records in the 50's but couldn'.t get very many runs before having crank problems. They talked a local scrap dealer into sponsorship ,,His name on the side and they could trade pound for pound and pick out all the flat heads that came in for scrap. towards the end they would just pull the enine apart, clean it and paint it red ,,two or three runs and then change blocks... no more expensive rebuilds.

[rsfyj]

Flat head Ford can not be measured with newer overhead engines. The Ford Flathead has won many races until the mid 1950s it will always have its own records. It was tops during its heyday bar none. And it will still go 120 mph today you cant drive it that fast on the streets. The Flathead has its own place forever. It does a respectable job in its class.

[MARTINSR]

The question was "What has anyone ever done to improve porting of the Exhaust ports from the valve seat all the way down thru the block to get the engine to breath better,"

The answer is EVERYTHING has been done and I mean EV-ER-EE-THING. If you do some google searching on these motors you will see that 60 years ago and longer, they had them "ported and releaved" to even regrinding the cams so that the exhaust was the intake and the exhaust ran out the intake ports on the top of the motor!

Here is a friend of mine running his fresh built flatty.

http://www.youtube.com/watch?v=7-HnSky_sb0

Brian

[MARTINSR]

How about these?








Here is a good article on the basics. http://www.hotrod.com/techarticles/e...e/viewall.html

Brian

[oldbogie]

Originally Posted by MARTINSR

How about these?








Here is a good article on the basics. http://www.hotrod.com/techarticles/e...e/viewall.html

Brian

Proving once again that there is no engineering problem so big it can't be overcome with cubic money!

Great pics, thanks.

Bogie

[fomoco56]

That picture of the blower induced exhaust system and the answers are what I wanted, not real practical, but if that is what it takes,
I will promote it.

[cobalt327]

Originally Posted by fomoco56

That picture of the blower induced exhaust system and the answers are what I wanted, not real practical, but if that is what it takes,
I will promote it.

If it's not a hush-hush deal, what specifically are you planning? Bonneville, street, drag, or ?

[fomoco56]

Thanks for the comeback, I am working on a 50 Ford for the Street, I would like the sound a little louder,not to the point someone says you need a muffler, by running straight pipes perform a little better and not run to hot driving slow on city streets.

[Irelands child]

Flatheads, even a near stock one can be very loud(rap!!). My GF many years ago knew when I drove by in my '53 Ford as the door knocker used to rattle. It did have the old steel pack Smithy's

[timothale]

In the 50's The kids i knew with flathead Fords said they could use a copper penny to plug the heat riser passage. I don't know if they put it in the manifold or block, but it added a lot more rap to the exhaust sound. I split my exhaust manifold on my chevy 6 and it really changed the sound.