79 to 85 Eldo engine swap

Ok, guy's, I know there has to be a gaziilion posts on this topic but I'm not finding them, so here goes.
 
How hard is it to swap the Olds 350 from a 79 Eldorado into a 85?
 
I have an 85 Eldorado touring coupe with 67K miles on it. the car is just sweet, but the engine has a noise that I can't pinpoint. It isn't a knock, more of a pop, and I believe it to be internal, but there is no marked difference in the performance of the engine, just this annoying noise. It doesn't do it when the engine is cold but once it warms up, it is definatley pronounced.
 
I know the 350 from a 79 will jump in here, or so I am led to believe, but how hard is it really?
I have a complete and running 79 that I drive regularly that I bought just for the engine swap.
 
Anything I need to know?
I know I will lose my digital mileage minder or whatever it's called, but is there anything else I should be aware of?
 
 
Steve
 

It's gonna be a chore to do, but since you have to complete cars. I suggest to loose the 79 efi and which to carb. 79 has 3 speed auto vs 85 overdrive,which you need to make sure tcc works. If you could trade 79 eldo for 83-85 toronado it would be a little bit easier. Either way disassemble donor first take pictures of everything.Then refer to them during the swap, there is going more to it than just swapping the engine.

log onto www.eldocountry.com. full tutorial on how to do it!!