Is it best to connect my subs paralelle in a bandpass encloser?

I have 2 audiopipe 12 inch 750 4o. in a bandpass with only 1 speaker term. to power the subs I have a boss phantom 4000 mono block. can that amp handle those subs if they are run paralelle. that's how I have them and push hard I was suprized. subs ran together that are 4 om. reduce to 2om. and you get most of your amps power. I listen to hard metal,but I still want my subs to beat. I have a Rockford 450.2 can I use that amp with them subs paralelle? I used a boss chaos 450.2 but it would turn off when I turned it up