Hey I got a 350 in my blazer and I was draining out the coolant from that radiator and it was pretty bad from all the wheeling its been through. Someone was telling me I should flush the block as well. I was wondering how I go about doing this. So if someone could tell me what I need to do, and what I will need to do it, that would be great. Thanks

Take off one of the heater hoses and the lower raditor hose.Stick a water hose in the end of the heater hose, hose away till it comes clean. Pull the other heater hose, flush out the heater core, and then the other hose to the block.

so take off either the one on the water pump or the intake manifold? Also I dont have the heater core hooked up at all.

Check your block's lower sides just above the oil pan in the center. Each side of my 71 GMC Sub's 350 has a brass fitting plug to drain the coolant from the water jackets.

Real simple.
Pull off your rad. hose going to the thermostat.
Pull off your rad hose at the water pump.
Pull the thermostat out.
Shove your garden hose into the thermostat opening and turn on the water.
Shove your garden hose into the water pump.
Shove your garden hose into the water pump rad hose.
Shove your garden hose into the thermostat rad hose.
A rag will help keep the water flowing through the components instead of back out the hole the garden hose is in. In other words wrap the garden hose in a rag and stuff it into the hole.
There, everything is flushed both forwards and backwards.

Put in a new thermostat and replace your rad hoses. Could even replace the heater core hoses too. If you paln on it, pull off both hoses and shove the garden hose in each one, one at a time obvisouly. If not the heater core will flush when you flush the block, just wait, all of a sudden you'll see it come out.
Add anti-freeze and check the mixture. Run the engine, heat on high, and recheck fluid level and mixture. Add either water or anti-freeze to get the right mix.
Add some to the overflow bottle.
Done. New hoses, thermostat and collant. About the only thing you didn't replace was heater hoses and the water pump. Although it would be easy to do while your in there.

You are wearing flip flops right. :lol: