Any tips on closing off the pre heater port on the stock exhaust manifolds if you're using an aftermarket air cleaner, but not headers? Also RV cams in a stock 350. Any pros, cons, company/model#, and testimonials would be greatly appreciated.

 

Are you talking about the heat stove that goes from the exhaust manifold to the snorkel of the air cleaner housing? Just remove all the sheep metal from around the manifold. If you don't plan to keep the car original anyway you can take the flapper out the exhaust manifold collector completely, it may be rusted in one position anyway. Not sure how hard it would be while still on the car though, probably difficult to get to. It would be good to do especially if the flapper is stuck in a closed or partially closed position. As far as cams go, I'll leave that to the engine gurus to answer. Moving this thread to the small block forum, you can post there now.

 

What year?

RV cams were designed for use in low compression (read "smog") engines, used in the '70s and '80s. They "recovered" some of the "lost power" by raising cylinder pressures to '70 and earlier levels. Good choice if yours is a '71.

Norm

 

I have an Engle 16-18 in mine. Some might call it an "RV" cam, in any event, it is pretty mild, 210/216 .472/.488 on a 112. Keep in mind the stock cam is like 194/.400. Here is a link to my build,
http://72.22.90.30/phpBB2/viewtopic.php?t=28012
As Norm alluded to, compression ratio is a key factor in choosing a cam, along with gear, converter, exhaust, etc.