Possible engine swap, 94 celica gt has a knocking/Tapping sound Options

[Yupe7]

So I am new to the Celica game and still green when it comes to the automotive field. (Backstory time) I bought a 94 Celica GT Coupe for 1200 pretty good steal for the condition that the paint and body were. But I knew I had to put some TLC into it for there was a leak from the oil pan and tapping/knocking noise from the engine as you accelerate. To get to the point I did a lot of maintenance to the vehicle but have left the engine alone till now. Had a friend who has more knowledge/experience when it comes to fixing and diagnosing vehicles. He heard the engine and said it was rod-knock. So to verify, I am adding motor honey to see if that's the problem. If it is anybody have an engine for sale or know what company makes rebuilt kits for a decent price? Appreciate the help thanks.