AJ-91-XJ said:
YEP! i did the heads on my 67 440 also on a slant six--- i dont know much about the heads on xj--motor does NOT burn oil!! or knok has been leepin for about a year -now bigger leak--so that also would make me loose power rite?
A bad head gasket, especially one of long standing, could certainly lose you power. But I'm curious as to what tests you have done to determine exactly what the problem is. have you done compression, vacuum, coolant leakdown, etc. to find out whether it's gasket or a valve or something else? Are you losing coolant?
The head on an XJ is a pretty standard sort of OHV head. Cast iron, not terribly hard to remove, but pretty heavy, and hard to get out and back in without a hoist or a hefty friend. Especially on the way back on, you'll need to be really careful getting it down slowly and straight so as not to damage the new gasket.
As Judd mentions, that mileage is pretty high, and you might find yourself opening a can of worms if the rest of the engine is worn. It wouldn't be the first time one has done a head gasket, gotten the compression nice and high for the first time in years, and had the rod bearings go a week later. Nonetheless, if you know it's just the gasket, and you're comfortable doing that kind of work, you could probably throw another gasket into it without doing much else, and not be risking much.
