I have purchased a tower hobbies voyager (all though I have not received it yet) and The engine is supposed to be mounted upside down, has anyone switched it to mount sideways or up right? does the tank position have to change if I change it? if i mount it side ways does it clear the fuselage? I will be running a gms 47 in it, what prop would be the best for it?

Have a look about this, it may help.
http://www.rcuniverse.com/forum/Good...2851518/tm.htm

I've found that my 4-stroke engines don't care one way or the other how their mounted. On the other hand,,,inverted 2-strokes have a bad habit of head-locking when the fuel builds up during the start up.
I do have several 2-strokes mounted at a 45-deg angle. (Muffler will line up on bottom of model.) No head-locking.