1994 gmc question & a possible process

We'll i own a 94 gmc sierra with the 5.7L, It's and Automatic and i just got it back from the shop because it was there having the engine swapped out for a used one. We'll i drove it today and it seems to be running right only thing is the idle seems a little rough , i don't remember it being so rough when i first bought the truck, i don't know if maybe it's cus the true dual exhaust is finally taking an affect on the truck itself giving the engine that rough tone and possibly messing wit the idle? Or could there be something wrong with the engine. IT seems as if while it's idling that it wants to bog down. I don't know what could be wrong with it but hopefully someone on here can help me out.

I was thinking of maybe giving it a some what full tune up?

"Plugs,Wires,Dist,Rotor" i had the oil changed while the engine was put in so i know soon i will have to drain it and refill it, but for now do you think the plugs and wires would be a good start or should i just wait and see? and if so what would be a good set of plugs wires and cap/rotor.

:screwy: :banghead:

Its hard to say for sure, but I would suspect the used engine as being a cause.
Excessive wear, ignition components may be faulty.
Used engines are a crap shoot because you never know what kind of condition they are in.

Exactly what i told my dad when he had that stupid engine put in, but no! i told him GET A CREAT ENGINE BUT NO! so now im here with a truck given to me and i have to spend my money getting it running right DAMIT!. I figure though i will get a nice set of wires and sum good plugs and a good cap/rotor and see if that works, they corrected the timing yesterday and it seems to drive alot better but like i stated the idle is really rough. SO hopfully doing that will actually help out. But we sha'll see what happeneds, and if you have any other ideas that i could possibly do with my mediocure knoledge of the Engine and it's matinence.