So I got a a set of 561s on a motor for my friends ride, was planning on porting to match gaskets on both the intake and heads. Is there anything I should look out for when I port them like on the old camel humps? Can I get a good gasket match without going into water jackets? Or is a good polish all these are good for?

 

The castings that are better suited for porting are the 374's and the 643's. while a little port matching wouldn't be a problem with the 561's i wouldn't port them to match old camel humps. The Lt1 might look like and sound like an old sbc but its a whole different animal as far as head porting goes.

 

the 561s are the worst of the aluminum heads as cast according to the Stock Eliminator racers who REALLY know such things and they are thin so most serious porters don't screw with them.

Do a search here on gasket matching and you will find nobody knowledgeable recommending it. Maybe it worked in 1980 but is not the right way to go on this stuff. Sure fully ported heads might endup gasket matched too but they will have the whole port worked not just a short section at the top.

 

I have a set of 643s that are ported and there was alot of meat removed, just haven't heard anything on this casting, this is why I asked.

I guess a good polish and bowl blend is in my future, thanks guys.

 

I wouldn't be afraid to port them just not as aggressively as a preferred casting. You will not get the same gains but a little is better then none. Also, if you don't have the supporting mods you're better off with just a little.