I'm in the process of match porting my head and I noticed quite a difference between my clifford intake flange .340 thick and my split dual exhaust manifold .515 thick. What do you do about this.Use a spacer on the exhaust
or shave the intake.

I also have a offy intake it measures .520 thick but I was told that a Offy is not as good as a Clifford but I don't have the Experince to say. So I could mount the Offy and the ex manifolds and the thickness is very close.

I also have a set of headers pt#5601H that measure .320 thick which is real close to the Clifford. But after reading Doc's and other articles I just as soon stay away from headers.

So I have many options to choose from. What would be the best combo for me? What would you do?

The factory flange thickness is a little over 1/2 inch (.500)
Is your Clifford intake manifold new or used?
DD

It is used

Sounds like someone surfaced it to get the manifold to match a thinner header flange.
Time to make some spacers.
DD