Will my subs become less "Punchy"

[Dakota Railsback]

I have 2 old-school L5 15s on 2 old-school Rockford Punch 800.2s all at 4 ohm,

Here are the box specs:

Width - 40 3/4"

Height - 18"

Depth - 18 1/2"

Port - The port opening is 3 3/4" wide and 13" tall

The MDF Board goes 12 ¾" back and extends 9" left into the box

If I change the port to be 4.75" wide and 16.5" tall and then also change it to go 13" back from the port opening and then 23" into the box to the left would it become less punchy than it is because the sq port area would be around 78". With those new port measurements the box would be tuned to 30hz and I was hoping to be able to play into 26/27hz.

[Joe X]

The enclosure you have is big enough for one L5 15 and you seem to have two on it, if you make the port larger that will reduce the internal volume further, Pretty sure you are not getting low a lot with that box.