302 Heads Emission Port

[parishpbs]

Have a set of 302's going to go on a 69 318 with headers. When I look at what I think is an emissions port under each exhaust port it does not look like these will be covered by the header flange and or exhaust gasket?

Do these have to be sealed off and how? If not plugged will I have exhaust leaks?

Thanks for the help.

 

[65Val]

Yes...they need to be plugged...thread'em and use small allen screws with thread sealer....file flat with port.

 

[318willrun]

1/4 inch tap, 1/4 inch set screw. invert so no filing needed.

 

[pishta]

zap 'em with a MIG welder: 5 minutes a side. Tapping cast iron is tougher than it sounds.

 

[72bluNblu]

1/4 inch tap, 1/4 inch set screw. invert so no filing needed.

This!

1/4" tap works well, the smog ports are almost exactly the right size already. And the set screw only needs to be a 1/4" long, so you really don't have to cut many threads into the head, just enough to get the set screw to sit flush with the outer edge of the head. A little loctite and you're good to go.

The ports are tiny so it's not as much of an issue, but welding cast iron without pre-heating and an extended, slow cooling period isn't recommended.

 

[parishpbs]

Thanks so much for the information. This site is awesome for giving and getting information.

Keep it safe on the streets.

 

[rigger3006]

jam in some tin foil and jb weld, has held up for years for me!