Single 10 louder than 4 8's

[00chevyS10]

I have a 2000 chevy s10 with 4 wolfram Cu 8's on a sundown sfb3000 powered by a mechman 240. I'm around 3.5 cubes after displacement with a 6 inch aeroport tuned around 36. Voltage holds steady at 14. My old set up an American Bass xfl 10 tuned to 35 seemed louder and deeper than my new setup. I expected 4 8's on a 3k to outdo the single 10 but they've been disappointing to say the least. I'm not sure what my problem is or if there is one.