On my previous car, an XF falconm I ran extractors, 2 1/2 inch exhaust, mildly ported alloy head, AFR intake with a holly 350 carb. I ran constant 14.1-14.4's with the 3 speed auto and 3.23 gears. The fuel economy did not change from stock.
I wouldn't bother with the electric fans, the clutch fan setup is fine (I tried the thermos on my XD and in the end I went back to the Clutch setup)
Whilst I agree the 250's are slugs they do respond quite well to exhaust and cam combinations, whilst I haven't personally done the cam, my XD has a twin barrel webber (on the XE manifold) Genies and 2" exhaust. Mines a manual with the 2.92 ratio LS Diff. Cruises nicely on the open road and delivers around 550 kms out of a 75 lt tank.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.