Headers and Port Divider questions

[blaze65]

Have a stock 200 with manifold and bell off to replace all Freeze plugs. Car is a mixed 68 block with 75 head. Has an Autolite 1100 and the LOM distributor. After I replace the plugs and assuming it runs OK, my plan is to leave the engine pretty much as is. I would like to go to a dual exhaust for appearance.

Is there any benefit to a header on this setup ? Like a dual output header Or just leave it alone and perhaps adapt a muffler with 1 input and 2 outputs.

Second question is that in the stock exhaust manifold, if I put it back, the port divider is gone. There looks to be a bolt right between ports 3 and 4 but the divider is long gone. Is this worth the trouble of replacing ? , will it make a difference if I don't , and lastly, on what I assume is the 75 exhaust manifold I see no hole to run the Choke tube. Was there one in 75 ?

Thanks

 

[FalconSedanDelivery]

First although the Port divider is debatable on much of a help , it can't hurt so I say put it in as for the choke tube , by 75 most were electric and just used outside , Not heated air , when working with a small motor / small hp , anything unless cost prohibited is a good idea ( in my opinion )

 

[bubba22349]

You could drill a hole in the 78 manifold for hot air tube, or auto parts stores like NAPA also had a universal hot air kit that you just clamp on to the manifold.

 

[CZLN6]

Howdy Blaze:

In your case, a stock log manifold with the inside cleaned up- Outlet opened to a full 2" and inlet ports from the head shaped to direct flow, a 2" head pipe from the manifold to the muffler with two outlets of 1 3/4" will give you a slight increase in response, mileage and sound, depending on what muffler you choose.

The '75 exhaust manifold will work just fine. It has some extra gussets and material and is less prone to cracking than the earlier ones. It will have some extra bungs and taps that you will not need. Just be sure to plug them good.

Adios, David

 

[JackFish]

You could drill a hole in the 78 manifold for hot air tube,

No, the port to the choke cannot be connected to exhaust manifold directly.
Otherwise it would blow exhaust into the choke, which it does when the "port" on the manifold fails.
There is just a chamber down there on that particular vintage of manifold.

 

[blaze65]

So does this sound OK

1 - Don't worry about fixing the missing divider between Ports 3 and 4
2 - Don't drill a hole in the log. Purchase a Stove oven/chamber that straps to the manifold
3 - Use 2inch pipe down to a single exhaust and then two 1 and 3/4 outlets out of the muffler.

Thanks