Land Rover Repair: 99 Discovery - losing coolant, head gasket replacement, head gasket failure

Question
John,
I added a bright orange dye to my coolant tank just over two weeks ago, and tonight, while topping off the water, I believe I see results. There is orange splatter on top of the front diff case, and all over the transmission cooler hoses. I can actually see dried orange residue on the left side of the block, apparently running down from the head. Although perhaps obvious, I have to ask, have you seen a head gasket failure such as this? Losing coolant externally, while not overheating, and running fairly well? I haven't tested compression, and not sure I need to at this point, but my other main symptom is a lack of power on long uphill grades. On the freeway on my drive home, I descend one ridge, and climb another, and if I can get up to 80+ on the way down, I still drop to 65-70 on the way back up, even under full throttle. That doesn't seem normal, even for a vehicle of this size. Would you advise a full top-end gasket replacement at this point? Not a foreign job to me in theory, I have done BMW and Volvo head gasket replacements. Anything unique I should keep in mind?
Thank you!

Answer
If you lack power on long grades, there must be a check engine light and codes.  Are there?  If not, whatever is happening is normal, as far as the engine management goes.  Leaks onto the ground are common, and head gasket replacement is the fix.  A valve job at the same time will probably give a small power boost