49 coupe split exhaust manifold

[dave2]

the exhaust manifold on my flat head 218 has 2 exhaust dump connectors on it...the front one looks to have been welded on...is this factory of someones aftermarket job?

[Sniper]

Old school hot rod trick  I went with these

[dave2]

the reason i ask is i was just wondering if the two parts are blocked off inside the manifold...if not i am just going to cap the front one and run single exhaust

[greg g]

Does the metal assembly between the outlets rotate?  There is a flap in there that may or may not still exist.  Can you rotate it to it's fully clockwise?  That is the position that allows gasses to pass through the chamber and not be directed towards the heat chamber in the intake.  The rear dump is the stock location.

[dave2]

es the flap is free and will rotate

[greg g]

Rotate it as far as it will go clockwise and secure it there with a spring or piece of wire, then you can cap the front outlet.  The flap is used to direct hot exhaust to a chamber under the carb to help keep the air fuel mix in suspension on cold days.  Of you only operate your car in the warmer months you should not have any problems.  I have min with the flap removed and a piece of thin stainless steel separating the two manifolds and have had no problem even on 20 deg F days.

[dave2]

thank you..i'll give it a shot

[1949 Wraith]

I would take advantage of the split manifold and and put on dual exhaust. It helps the engine breath, as the rear cylinder has basically no back pressure and loads at the front. I had the manifold cut on my '38 Dodge 218 and she works very nice, the heat riser area was cut out and I have never had issues with cold running even in below freezing temperatures. I will probably do the same to my '51 Dodge truck when I locate a spare exhaust manifold.

[Robin (UK)]

3 hours ago, 1949 Wraith said:

I would take advantage of the split manifold and and put on dual exhaust. It helps the engine breath, as the rear cylinder has basically no back pressure and loads at the front. I had the manifold cut on my '38 Dodge 218 and she works very nice, the heat riser area was cut out and I have never had issues with cold running even in below freezing temperatures. I will probably do the same to my '51 Dodge truck when I locate a spare exhaust manifold.

I have to agree. A split manifold or headers with dual exhaust is the single biggest change you can make with a bolt-on to these motors. It transforms the car.

[Dartgame]

Often when these are split the front cylinders are blocked off from the rear - with a welded in plate at the heat riser. I'd check and make sure...Or do as suggested and keep it dual.