On my se's I did 144.0 3.9 cuft tuned to 38 hz. And did 143.8 4 cuft tuned to 33 hz. So a little increasein the differant tuning but not huge. All done db drag style sealed I think they sounded a 100 times bettter tuned lower this was done on a zx1500.1 just a red top in front stock alt. So maybe more juice wouldve helped don't know.
Dude, a 147.3 is a **** good number for no electrical, especially at 33hz!!! You might even be louder if you try lowering your subsonic filter a bit. Those subs will get the lows like crazy.
they get loud i'm doing a 43.5 with a single se 10" reconed with better parts.
tune higher for a louder # would start @38hz and keep cutting the ports. are ur ports low in the enclosure? how much room between the tailgate and port? is ur box braced well? ur alt is plenty with that amp, get a 2nd battery kinetik 2400 or pm 3100!