Mods to the intake for these heads
 

Looking at a set of Bowtie heads part# 12363425 and on the GM site its says the following

Ports in production and after market intake manifolds must be modified to match the intake runner entrances.

Now I think I have to raise the roof of the port up, but will I have to raise the floor also ??

or is it a matter of port matching the intake to the head

I used to run a set of Bowties with a Victor Jr. and just had to port match heads and intake to the gaskets I was using.

I agree. The main part of the port matching will be in port matching and raising the top of the runner to match the raised runner design of the head. If the bottom of the intake manifold port is slightly lower than that part of the runner in the head it won't hurt performance. There would only be a significant gain in welding and reporting the bottom of the intake manifold runner if there was a large mismatch with the intake port in the heads. Even then this would most likely only be seen in a small part of the rpm range.

I'll agree too.

A helpful suggestion though. If you are buying these new, you may want to seroiusly consider instead to looking at aand buying the ones that Curtis Boggs is selling with a full CNC Port job where he puts his own Race Flow evelopment Ports, bowls, chambers and everything into a bare casting. The cost is not much more than buying those aluminum bowties. The Bowties can be made to be bad to the bone with professional porting. These are badder.

www.raceflowdevelopment.com

Very highly recommended by me.

Ed