Why don't the ports line up better from heads to intake?

[pwcracer]

I set the intake gasket on the heads on my car and they line up well (Meaning the gasket intake opening is the same size of the gasket. when I placed the gasket on my stock intake, there is at least 1/4 inch gap all around, where the intake port on the manifold is much smaller than the intake port on the head. What is the point of this? I have been elliminating bottlenecks in my system, and now I think I ran into another one, I am installing GT40 heads, but I have to use my stock lower intake due to my Kenne Bell charger, only working with the stock intake.
My car is going to suck I bet

 

[emagdnim]

You have to port the intake to match the heads for best performance . Spend a night grinding and it will be worth it

 

[pwcracer]

I was thinking about that, but do you think there would be much to gain, when the runners in the intake manifold appear to be the same size as the tiny ports?

 

[emagdnim]

The lower intake on a 5.0 is a big bottleneck you need to port this if you want to make decent power unless you go aftermarket upper/lower intake... a good ported lower with the stock upper can be good for 300hp with tons of torque.

 

[tmoss]

The lower should absolutely be ported for best power under a KB 1500. I've done a bunch and dyno tested a 80lb-ft increase peak and gains all the way from idle through the whole curve on one customers car who did before and after dynos with no other changes.

 

[89MustangGX]

Is there a way to swap to the GT40 KB or does it require a whole new blower?

 

[tmoss]

KB 1500 - stock lower only

KB 2200 - GT40 style lower only

 

[89MustangGX]

KB 1500 - stock lower only

KB 2200 - GT40 style lower only

Ouch.