Flushing out block

I've got an engine that is full of 35 year old rusty water/coolant and I'm looking to flush clean while still intact in the car but I don't want to run it thru my new water pump and intake if possible.

I've fabricated a couple fittings for a hose connections at the front (see arrows on drawing) and was thinking of either, attaching the intake  or fabbing up some fittings for the heads.

With this setup I feel that I could power flush with an air pressure/water combo and maybe even use a pump to circulate a rust removal  product throughout the block to loosen the crap up further.

Does anybody see a problem or any issues with this contraption? Should this work?  I'm sure I wont get all of the crap out but I feel any little bit would help.