fram are good filters, any way this is the torque stuff:
you tighten the bolts starting with the two centre then in x's i.e left of centre two top, and right bottom, left bottom, right top, then next larger x (next door but one to centres!)
tighten all to 15 ft lbs, then mark them with tippex at 12 o'clock, same sequence move em all 15 minutes or 90 degs, then another 15 mins, then all the tippex should be at 6 o'clock or next to exhaust manifolds!!!