How to determine small port vs larger port 273 heads.

[1967Barracuda]

So I ordered shorty headers from tti for my 1967 Barracuda with a 273 2 barrell engine and I have to share this disclaimer from tti:

273-318 BLOCKS: PLEASE NOTIFY US IMMEDIATELY IF YOUR 273-318 cylinder heads have the small port size of 1.550 x 1.090. Modification will be required to the ports for
the headers to seal properly. Modification will be done prior to coating, please allow additional time for this process. (An additional modification fee will apply)

Is there an easy way to find out the port size or do I need to take the exhaust manifolds off and measure the port size. What instrument is best for this or will a standard ruler be fine.

 

[toolmanmike]

So I ordered shorty headers from tti for my 1967 Barracuda with a 273 2 barrell engine and I have to share this disclaimer from tti:

273-318 BLOCKS: PLEASE NOTIFY US IMMEDIATELY IF YOUR 273-318 cylinder heads have the small port size of 1.550 x 1.090. Modification will be required to the ports for
the headers to seal properly. Modification will be done prior to coating, please allow additional time for this process. (An additional modification fee will apply)

Is there an easy way to find out the port size or do I need to take the exhaust manifolds off and measure the port size. What instrument is best for this or will a standard ruler be fine.

View attachment 1715981914

there are no large port 273 heads. What heads are you running?

 

[1967Barracuda]

there are no large port 273 heads. What heads are you running?

I will find out once I get the car back from the shop but it is a 1967 Barracuda fastback with a 273 2 barrel engine all original basically.

 

[toolmanmike]

I will find out once I get the car back from the shop but it is a 1967 Barracuda fastback with a 273 2 barrel engine all original basically.

View attachment 1715981921

Probably 920's in a 67. Small port unless they have been changed out.

 

[1967Barracuda]

Probably 920's in a 67. Small port unless they have been changed out.

So 920 is the casting number which will indicate small port heads. This way I can just pull the valve covers correct?

 

[toolmanmike]

So 920 is the casting number which will indicate small port heads. This way I can just pull the valve covers correct?

Yes

 

[4spdragtop]

Take valve cover off and look for casting numbers. That "MAY" give you an idea on ports. Factory 273 heads port sizes I believe were all the same.

 

[MOPAROFFICIAL]

The early ones are critical below the port, theres less flange/sealing surface.
Smog head for instance have the air injection which adds sealing surface.

 

[toolmanmike]

So I ordered shorty headers from tti for my 1967 Barracuda with a 273 2 barrell engine and I have to share this disclaimer from tti:

273-318 BLOCKS: PLEASE NOTIFY US IMMEDIATELY IF YOUR 273-318 cylinder heads have the small port size of 1.550 x 1.090. Modification will be required to the ports for
the headers to seal properly. Modification will be done prior to coating, please allow additional time for this process. (An additional modification fee will apply)

Is there an easy way to find out the port size or do I need to take the exhaust manifolds off and measure the port size. What instrument is best for this or will a standard ruler be fine.

View attachment 1715981914

Here's what you should find.

 

[GTX JOHN]

If the car is original = Definately small ports.