new to isuzu

i just got my first isuzu it is an 89 pup and befor i lower it i want it to run right and i am about to through a rod it is really loud noise right befor i change gears is that right? and would it be easer to get a new motor are fix what is wrong with mine? and if i need a new motor what type of motors are my options for that? i really hope some 1 on here can help please!!!!!!

there is a place online called S&S engine remanufactures i got a reman 2.3 long block from them for about $2,000.00 7 year 70,000 mi warranty