awhile ago i hit a deer with my truck.  it hit on the drivers side headlight and that corner of the bumper after i went and replaced all the parts i noticed that it makes a rather loud knocking noise when ever i start the vehicle and when ever i drive the fan seems to rub on the shroud and when im at a stop sign on an incline the fan noise increases.  when i did a tune up on it nit ti long ago i noticed that the passenger side header was sitting on the frame rail, well more so the flange that the bolts go through from the header to the rest of the pipe was sitting on the frame rail, so how can i diaginose what my problem is without taking it to a shop? my thoughts where that i bent the frame or shifted the motor somehow.. if that is what it is, is there an easy way to fix this?  

If it were me I would just trim the shroud so it did not hit any more after you get rid of the fan noise it will be easer to hear for the knocking noise but that might be the fan too. Try measuring the frame to see if it is bent I once got a 1960 Volvo car that was sitting on a shortened blazer frame turns out one side was 1/8the shorter then the other side this was not from an accident though it was just cut and welded wrong but if its bent it should be easy to figure out with a measuring tape.  

Do not trim the shroud as it is there for a reason. It sounds like motors mounts were damaged as only that or bent frame can cause your alignment issues. I would check all engine and tranny mounts first.  

Yes shroud is there for a reason but if the fan is hitting cutting a little away should be ok I have ran with out shrouds before as long as you don’t have a wildly built motor there is not much of an issue with heating and if there is its only when your sitting still idling for a long time. I don’t think trimming were it rubs will effect cooling enough for you to notice.  

The point is you need to find cause of misalignment rather than trying to trim you way out of it because it is a sign that something is not right.  

ok so trim the fan shroud, measure the frame rails, and check engine and tranny mounts, what about the transfer case could that be hitting as well?  and would it be worht putting money into to fix up a v6? or would it not have enough balls to get the job done out on the trail?  because i'd really like to fix it up but i just don't know if the motor that is in it will cut it, and i wouldn't want to do a swap, being that it's a OBD2... i'd like to find something like a 1986 GMC high sierra step side or a late 70's early 80's chevy 1500 step side.  

What makes or breaks a 4x4 off road is axle ratio gears not engine size. Many think they need a bigger motor when what they really need is a better set of axle gears.