How restrictive are stock exhaust manifolds?

[69Falcon]

I need to do the exhaust on my '69 Falcon, and I'd like to keep the cost down as much as possible (saving up for the new head!) which means just replacing my stock exhaust. (The pipe between the manifold and muffler is bent and leaking at the manifold.) So here's the silly question: If I were to leave the stock exhaust on with Mike's new head, how much would performance really suffer? Eventually I'd put headers & high flow exhaust, but for $$ I'd probably leave the stock manifold in place for awhile. Any thoughts?

Also, does anyone know where to buy a new exhaust donut for a '69 200 I6? I can find the pipes, but not the donut listed anywhere...

 

[CobraSix]

I'm not sure mike's new head will even work with a stock manifold. I think you have to go with the headers, pattern is different if I recall correctly.

Try www.npdlink.com

It looks like it's part number 9450-16A for 69 mustang. Look on page 103 of the exhaust one (You can download the section). It has one there 9450-D and they are individual to the different types of exhuast. The diagram has this part listed at the start of the exhaust system and it looks like the right part. 9450 is the one listed for mustang 6 cylinder exhaust.

Slade

 

[Gene Fiore]

I'm not sure mike's new head will even work with a stock manifold. I think you have to go with the headers, pattern is different if I recall correctly.

Are you talking about the bolt pattern? How could that be different? Then no existing headers would work, let alone the stock manifold. Am I confused?

 

[69Falcon]

The more I thought about it, I think its the siamesed #3 and 4 ports, are they also siamesed on the stock exhaust manifold? If so, I doubt it would matter because the ports basically feed into a log.

 

[james singleton]

69 Falcon, For what it is worth, I ordered a new stock exhaust manifold from Restore Mustangs (www.restoremustangs.com/exhaust-manifold) that claims to improve performance on 64-67 six cyclinder engines (200 & 250). The manifold is designed after the stock 68-73 manifold and supposedly has a larger port and more free flowing design in conjunction with a larger diameter exhaust pipe & muffler. Since you have a 69 Falcon with a 69 engine (?) you may not notice a difference from the stock manifold that you were running, but I have a 66' 200c.i. engine and was not necessariliy looking for header like performance. My wallet was a consideration, and I think you will find this stock manifold to be about half the price of headers. I hope this is of some help!?

 

[CobraSix]

Mike is basing the Aluminum head on the Aussie 250/2V head minus the siamesed 3-4 port that is on those heads. The stock US exhaust manifold does not fit the Aussie head if I recall correctly, but I'm not 100% sure on that.

 

[matt1967]

I thought only the Argie heads don't work with US exhaust.

 

[CobraSix]

I know for sure teh Argie can't use the US manifold, but not 100% sure on the Aussie. Mike will hopefully chime in to set me straight.

Slade

 

[addo]

A cast manifold off a log head will not seal on a 2V head. Ford sold the 2V equipped cars with headers, from the factory.

 

[hasa68mustang]

slade I believe mikes head retains the us manifold pattern.