doing my 136 swap, and need to drain all the coolent to pull out heat exchangers and put new ones in, how do i drain it?

Remove the tube from the engine block...usually black... empty it into a container try not to spill, and do it when engine is cold. Let the pan that you are draining it into sit for along time... make sure everythin gets out. We leanred this in shop last year :fluffy:

Remove a hose and suck all coolent out with a shop wet vac. replace with new.

Ditto on the shop vac, clean and fast , no spill . Start at the thermostat.