engine swap

i have 86 cherokee with a 2.8 in it. it has bad rod an main bearings an a bad crank. i have an 84 cherokee that has an 3.1 in it that some one else installed. pulled this engine out because tranny was bad had to pull oil pan to identify engine. the 86 cherokee has manuel tranny my question is will the 3.1 work. thanks for any advise