Originally Posted by pishta
The ports are smaller inside than a stocker.

In some cases, that was true.
440Source did have a run of rough castings that had the smaller internal passages but they have improved them since then.

One thing to make a note of:
The thermostat sits higher on the aluminum housings by 5/8". This can interfere with the fitment of the A/C compressor if you are considering an aftermarket Classic Auto Air kit with the small Sanden compressor.