Porting Stahl adapter plates
 

I am doing this for the first time. What is the right way to do it.
1. make them the exact size as the head and dont worry about blending into header or
2. make them the exact size of the head and then taper out to the exact size of the header
or is there a better way.
I could do the second but there would not be much room especially on the 2 middle cyl for gasket sealing
This is for a bracket car sorry for posting in the stock/ ss section but I figured I might have better luck here since s/s cars use them.
Thanks in advance for any help you guys can give me.
Rob

Engine is a 398 ci late model LT1 with AFR 227 heads, plates are the 5/8in thick alum ones

Re: Porting Stahl adapter plates
 

same size as the head.