Quote Originally Posted by GasGuzzler View Post
It refers to the angles on the valves and valve seats. The more angles the smoother the transition from chamber to cylinder for the air/fuel mixture. As far as cost, depends on the machine shop. Be prepped to pull the heads.
Good explanation Nate.

Quote Originally Posted by GasGuzzler View Post
If you have the motor apart for a big build and you're putting on ported heads, etc. it makes sense. If you're considering this by itself it makes no sense to do.
Yeah, but I think he is wanting to go FI, so the will be building it slightly. Since he is going FI, once you take the heads off and have them cleaned up, make sure to get GM metal head gaskets and get some ARP head studs--they are not TTY and are stronger than the stock ones. It is a good idea to use them with boost.