Classic/Antique Car Repair: rad flush, pontiac laurentian, heater hoses

Question
Hi R.J.
I wrote to you a few weeks back about the rad overheating on the 230 6 cyl.chevy engine in my 64 Pontiac Laurentian.
I had a pressure test done and it was good.The mechanic said he checked the thermostat and it was opening and closing.I assume the rad cap is part of this test.
I did a home flush with Prestone rad cleaner which did bring out some rust.I ran water through the system until it ran clear.
Still,it overheats.
I would like to try a couple more things before I take it to a rad shop.
A friend that used to work in one suggested I remove the rad and fill it with 'CLR' or a stronger rad flush solution available at NAPA. He said its best not to run this through the system.
If I didnt feel comfortable removing the rad,I could leave it in but remove the hoses from the engine.
There is a big hose on the top and a big hose on the bottom.Two smaller hoses run from the engine to the heater.
I think I should disconnect the heater hoses,and the top big hose,but what about the bottom.Should I disconnect it from the engine and stuff it with something?
I appreciate your exretise,thanks in advance!

Answer
Barry;
Hi still getten hot, well u just said u have a big hose on top is it a flex hose or a std. round hose w/o a spring or coil around it, as some times those big hoses will suck closed when driving so check that out, also how is the rad. cap that will do it also. as the cap is off when u do the rad. psi test. try a new cap. U can jus remove the top & bottom hoses than tape the  holes shut or plug them. than  fill it with the stuff and let it set for a bit or what it tells u to do. if it still geta hot, I would remove the thermastadt and try it that way. is the fan close enough to the rad. clutch fan ? flex fan ?  
RW