straw1628

Now that I have gotten lots of info on my car I have another question. My 66 has a smog pump on it. I want to do performance mods ie carb, intake,maybe cam ignition, while keeping engine mostly stock. Are the stock smog heads more restrictive than normal 289 heads, and will it be worth it to put a mild cam in with stock (rebuilt) heads? I am just looking for a little more performance. Thanks for everyones help

JMD

I do not think that the smog heads will cost you much power, if any, being that they are 1966. All you need to do is plug the holes.

The engine will respond to performance upgrades just fine.

Starfury

All those things will help, but you'd get a lot of gain from port matching the exhaust on your heads, at the very least, if not a full port job with larger valves. IMO, it wouldn't really hurt originality. You're still going to be using the OE heads, and the improvements aren't visible externally.

groho

they sell the screw in plugs for the smog ports, but they are not cheap somewhere in the neighborhood of $12 a piece. They are specially tapered to completely block the air injector port.

straw1628

Can I get the plugs at year one or something? As far as the heads, I thought about opening them up a little bit as I had heard they are lacking in exhaust valves. I have limited knowledge about all that. Any more info is greatly appreciated. Thanks

fast66

If you are going to leave the heads on the engine while doing the cam/intake/Etc mods, what you can do (and this is a little dodgy) get an oily rag, and stuff it into the exhaust port of your head you are going to work on. When looking into the port, you will see a bulge on the inside. It is very obvious. This is where the smog air injection comes in. You can use a die ginder to remove and smooth much of this bulge, and by doing so improve the flow. As mentioned above, an exhaust port match wouldn't go astray while you have the die ginder handy. Avoid a gasket match however. WHen you finish each port, get a vacuum and such as much of the gindings out, then very carefully pull out the rag you stuffed in there. This will prevent gindings from going into you cylinders, or valve guides As I said this is a little dodgy, but personally I think better than removing heads and trying to reinstall on old gasket surfaces that have been cleaned with a paint scraper.

A cheap plug for the smog ports is the correct thread grub screw. Just take one of the injectors fown to your local bolt supply company, and they should be able to help you out for much less than 12 each!
Just a note, when you remove the air injection manifold (the 4 tubes) there will still be a tubular nozzle in the head, (they get gummed up with carbon, an may come out with the fitting, or not) you should endeavor to remove these aswell.

Then for your mods, If you were to then go with something like the Edelbrock Performer manifold and cam, with a 4bbl carb and some headers, you should see about 180-200 REAL hp at the wheels. Much healthier than the 140 odd from stock.
Cheers

straw1628

Thanks for the info. I am planning to pull the engine, and thought I would have the heads done by someone. I want to paint etc. That would be great hp at the wheels. I just want to make a nice street driver out of it . Thanks again

rmodel65

if you want a great head up grade for a couple hundred bucks look for a set of 5.0 explorer heads they are actually gt40(little better than a set of 351w) i

ky

you can get some pipe plugs (the allen head set screws) for the holes.

no need to buy the "special" plugs. its just someones rip off invention.

there still will be some short 1 inch tubes inside the ports if you plug them up. the wont really affect anything but you may want to have them removed.

Starfury

Fast66, when you port-match the exhaust, you're matching it to a gasket. You don't want to take it all the way out tothe gasket mark, you want to leave about 1/16" extra, but you're still matching to a gasket scribe. The idea is not only to remove the exhaust hump, but also to smooth the opening from the valve area all the way to the gasket surface.

When I did it, I just stuffed the ports chockfull of wet paper towels. I went in a good inch and a half with the die grinder and madethe port transition niceand smooth. After I was done I cleaned everything with liberal amounts of brakleen and compressed air.