It seems to have good power, but when it shifts into 2nd gear it all of sudden seems like there is not much power and has to get back into higher RPMs to get caught up.. Almost like the gear is too tall. It seems to mostly occur while the engine is cold.

5.7L V8
3:42 rear end (i am pretty sure)
Happens with and without A/C on.

Any ideas?

 

Are you sure it's going into 2nd at all? It might be skipping and going into a higher gear. Count the shifts and make sure your getting all the gears.

 

Wonder if that year has a TPS?? Could be that.