Doesnt want to turn over could be a number of things:
a) not enough current getting through, needing higher zzzzt from the jumper vehicle - battery leads corroded or loose, as Cal suggested, or starter solenoid contacts gummy or dirty,
c) engine partially seized. Does it turn over by hand? Does it have oil in it?
d) muffler part full of rust, mud or potatos

. Does it start any better with with the exhaust disconnected?
Start with the simple things first.
Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.