Is their a big problem with using a air injection head, for a hi po big valve motor? I already have the head in the machine shop an some work has allready been done to it and I just now found out that it has air injection ports !!!! The motor is going to go into a 64 DartGT so I don't need emissions. Can I safely heve them sealed up, mabey with a small spot weld? If this is a big screw up I need to know as soon as possible so I waste as little money as possible.

Thanks in advance.

Andyman225

A block off plate is easy enough. The holes in the exhaust ports are tiny, and could be easily capped with something.

It's just more work than starting with the non-emissions kind, unless someone has a failure story. I'd like to hear it, because I've got a worked head with the air injection and just a block off plate. It hasn't seen enough service to know if there could be problems.

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1980 Aspen 225 super six

The heads with air injection are about 20 pounds heavier than the ones without, and the extra passages limit the degree to which the air injection heads can be reworked (ported/polished).

Where does the extra 20lbs come from?

There is a long air "passageway" cast into these heads and there is a little more metal in the exhaust ports and in the rear of the head where the inlet tube mounts. It's all extra weight but some say that this extra metal makes these heads stronger.

If you want to block the passage, use a welded shut tube flange at the rear of the head or you can tap each small hole with 1/4 - 20 unc and then thread-in bolts until they bottom-out, then keep turning them until the heads snap-off.
DD

*whew*, what a relief. I've been looking for a solution for the weak \6 heads for ages! [/quote]

Thanks for the speedy replies
Thats a huge relief to hear. I can deal with an extra 20lbs. After all I've been dealing with an extra 20lbs on my body for the last 3 years.
I finally going to have a big valve head soon!!!!!!