Should this be smoothed out more? Is this done correctly? it looks like the diffuser is going to get in the way of air flow? Any comments?

 

Go up!

Also, think about the cross-section of the port. Right now it's very pinched in the middle.

 

Is porting the upper part, part of a standard street port? I'm using the mazdatrix templates. Does porting the upper change the port timing or whatever?

Also, what about the middle lower part now? What do you mean pinched?

 

I ported a 79 12a and 91 13b in your case just look at the port from the outside and remove as much material blocking a smoth flow around the insert. If you remove more than that the overlap would be too much for street use.

 

Please check my other thread that got more traffic out

https://www.rx7club.com/forum/showth...threadid=88031

 

I mean the middle of the port - not the port entrance. You changed the port timing by altering the entrance. Now you have to alter the middle of the port to effectively use that.