Changing Rear End Need Some Info Plz!

I'm In the process of changing the rear end of my 1987 chevy s10 the truck has a 350 with headers & flow master no cat's 3 speed auto.. i was just wondering if i change the stock rear end to a 342 rear end will i notice alot of difference ??

Depends on what's in there now. Some early trucks had a 3:73 stock. If it's a 3:08 now you will wake it up some.
the 3:42 is a good all around ratio.

there could even be a 4.10 ratio in there