polyfill in a ported box?

Ok I built a 4.75 ft^3 net 65 sq in port tuned to 33 hz as advised by Aznboi. kicker 15L74 wired to 2 ohms, kicker 08zx750.1, big 3 upgrade entire back half of car dynamatted. It slams so hard it hurts. The gain is in between the 1st and 2nd mark on the amp. I am thinking it may be port noise possibly. Will adding polyfill smooth it out or not? Pioneer deh 4900ib HU. I have the bass boost on HU @3 and subwoofer setting @ -10.  I would also like some advice on some decent SQ speakers .(kicker 08zx350.4) 

make a mess if not done correctly

you telling us where the gain is means nothing without knowing the input. The gain is not a volume knob. An amp can put out full power with the gain on the lowest setting or the highest...doesn't matter. Also make sure all seams are completely sealed...a leak in an enclosure can make a big difference. I doubt it is port noise as there is plenty of area.Custom Enclosure Design

I put the top on last when assembling the enclosure, so that i could silicone the joints easier, even around the port. with the 4 1/4 inch opening and the sub cutout I was able to silicone the top panel also fairly easily. I turned the gain down completely and just turned up sub volume on the HU. I am assuming since I built an enclosure for spl and no sq that is probably as smooth as a response as I will get. It seemed to help.Thanks again for the thread Aznboi. You can feel the air move outside the car. I didn't really want to try and remove the enclosure to polyfill it anyway. I had to remove the back/drivers seat plus trim some sheet metal back after pulling the interior plastic panels just to get it in. I only have 6 inches from the port to the trunk lid and the enclosure is up against the rear seat. Is that adequate port clearance?

What kind of noise is it...?M.E.C.P & First-Class

Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!

I also didn't take into consideration how stiff the sub is straight outta the box into the enclosure. maybe 30 mins play time so far. plus I was used to the sound of the two cvr 12's before. There is a big difference in the output. It is not really a noise just not as smooth of a response as I expected. I have been tweaking the HU settings with the  amp's gain set to lowest setting, It is coming along. I was just curious if the polyfill would smooth it out some or is that not a good idea in the ported enclosure,( I thought to remove the sub and usea fabric mesh of some sort to keep it from entering the port),  or should I wait until the sub has more play time?

As far as the input I am not sure The cap readout says 14.10 drops to 13.5 on hard low notes. I don't know how to test the system to see the accurate voltage or amperage I am really getting.Would autozone be able to tell me my Alt. output?

I am hoping I constructed the enclosure correctly  the internal volume is 30x16 1/4x24 port is 4.25x16.25x27 1/8  I allowed .4ft^3 for sub displacement and four 2"x3.4" braces 16 1/4 tall I came up with just under 6.35 gross before any displacements.

tha is supposed to be 3/4" on the braces not 3.4"

If there is a leak will a 2nd silicone on all joints and overlapping panels of dynamat  on the interior panels help or will that change the internal volume too much?  Or do I have to rebuild the enclosure since the glue is set?