I just bought a new polishedHigh flow water pump and Im replacing my thermostat and hoses. Im wondering, what's the best(most effective) way to flush the block? I have a 65 with a 289. Thanks

 

The best way I know of is to buy one of the Prestone Flush 'n' Fill kits. You cut a heater hose and insert a tee (with a cap for normal use) then connect a garden hose to the tee and turn it on. There is a diverter that you put in the radiator neck to control the outflow. Run it till it is clear, drain, close it up and add coolant mixture.

Oh, and have the heater on its highest setting to clean that out as well.

 

in addition, pull the thermostat out and take the upper hose off of the radiator. Fill the radiator with water and keep the hose filling it while you drain the block thru the top hose. starting th engine helps flush quicker, but it gets messy when the water hits the fan.

 

Turning the heater on or off does not affect coolant flow through the heater core.

But yeah, you can either buythe Prestone flush kit, or take it to a radiator shop (not Jiffy Lube)to get it backflushed. Most shops don't have actual backflush setups, just coolant exchange machines that are designed to exchange old coolant with new.

 

No offense intended, but don't do what jlg2002 said. You'll get the system flushed better with the Flush 'n' Fill kit.