I'm using an 87 f-150 as a donor for my 55 *****'s project. I'm already set on converting the 300 over to carb, and I've already bought all the parts. As you can see I still have this air tube attached to the head, and that's the final remnant of the old EFI system. I got the big nut off the top of it - so I can plug it there. Ok? The 6 attachment points are not budging. I'm considering cutting the tube at each location so I can get a six point socket on the nuts and presumably plug each one. But, I'm not positive I'm doing the right thing or what purpose this tube played before and what it will do now with a carb? I've read a bunch of carb conversion threads but no one touches on this piece. Any help is appreciated.

 

The only reason to leave it on is that it makes a convenient handle to take off the head. The holes do not go into the combustion chamber and they are easy to plug. Go ahead and cut them off. I just did mine. I just matched the threads with what came out. P B blaster helps. I would appreciate any updates on your install, thanks.

 

Thanks. So here's a close-up of the smaller 6 nuts. Is this a collet style - where the actual pipe is just held in with pressure from this nut? The head is so dirty it's hard to tell. Also - if the ports don't go into the combustion chamber - then what do they do?

 

Hi Willys55 and welcome to the forums.

Blech, that is one grimy head.

Fortunately, that's most likely nothing more than a bad valve cover gasket.

The air tube holes do go through into the head. They're there to supply fresh oxygen to the exhaust ports to help the catalytic converter to a better job. As Brian said, soaking them a bit can help get them off. Also, cutting them and then putting a deep socket on them might do a better job of removing them. After that, just find some bolts that have the same thread pattern and put them in.

Otherwise, you can just leave it, and plug the main opening. It shouldn't hurt anything.

 

Thanks. I'll post follow up since it was requested.

 

exhaust ports

 

Oops, you're right. Fingers going faster than my brain.
Fixed.