Need port calculating/box length help ....

[sixpac440]

The sub is a JL 10W0-4. Downfiring
03 S-10 ext cab

The data sheet http://www.jlaudio.com/subwoofers/pdfs/ ... W0_MAN.pdf calls out the port specs for a 1.25cf box.
The sheet doesn’t say what the frequency tuning is.

Minimum ported enclosure is .90cf and that’s what I want.

I can seem to calculate the port/ports for .90cf.

INTERNAL dimensions for the box are:
6.00 H" x 10.75" D x ?" W

The driver displacement is .050cf
Of course I don’t know the port displacement.

I want the port/ports to fire forward so it/they have to fit within the 10.75" front to back internal dimension.

I have some thin wall 3” I.D. PVC but will get what is needed.

SO ... how long will my box need to be and what size port/ports will I need?

Thanks
Kevin