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.

[Yupe7]

hey, so I end up buying a used engine from an import shop that I have done business before with. I am like 3/4 of the way done with the engine swap but when I drained fluids I also drained the front diff fluid I know Its gear oil for that smell is not hard to forget, but I am trying to find out what type of gear oil is needed, is it the same as for the manual transmission (I have an automatic sadly) or is it different? The spec for the manual is 75w-90 GL3