I have a 1995 Chevrolet Silverado k1500 4x4 with the 5.7 liter 350 I've just bought it been fixing it up truck ran fine now problem till I discovered the radiator had a pin hole in it so I replaced the radiator and the thermostat then started to overheat replaced thermostat again still overheating replaced the clutch fan and it still overheating am not able to drive it (the radiator that came out was a thin one and the one that was put back in is a little thicker) what else could be my problem

 

Did you bleed the air out of the system?

 

... and we are all assuming you changed the radiator cap? Also assuming you got a proper mix of water in the system.
Systems don't run well on higher proportions of coolant/water. Water is what transfers the heat more efficiently.

 

Are you sure it is actually overheating and not getting a false reading from the gauge. If it is a real overheat problem it could be that your engine block is partially blocked and may need to be flushed.

 

Glycol is a desicant. It attracts water, used alot in dehydrating natural gas, that is the reason use a mix of water/coolant.