The motor is a 4.0L unit BTW and the core is ~2" thick from memory.
Jac Mac, I'd been thinking of the design of the ducting using the same principles as for an airbox (which I've some experience of doing on motorcycles). Its funny to find a real use for understanding
Bernoulli.
Boiling it down I think that theres basically 2 options:
1. 21"x17.5" (367.5 Sq") laid over to 30 deg from the horizontal.
2. 21"x13.5" (283.5 Sq") and vertical, but 23% smaller in colling area than option 1.
The outlet issues are going to be identical in both cases, so I think that can be taken
out of the decision making process.
Who'd chose what option?