alrighty, todays the day I tackle this problem...
thanks for all the replies and advice!
I'm probably wrong about the year 1ton chev truck I salvaged the heads from... thought it was an 03, but most likely was a 93, as I've read elsewhere chev changed it's motors again after 96? anyway, the heads are indeed 906 casting vortec, worked by D&W engines in calgary to accept the comp cams xtreme 4x4 x4270h cam .480/.498 lift @ 107 centerline...
so I'll put the thermostat in. I already tested it on the stove in a soup pot with my infrared gun, it is a mr gasket hiflo/nofail 180F, and opens at roughly that...
the waterpump is the same 70's long neck that was on previous motor, and pulley is a smaller chromed one, but was also running on old motor... as I understand it, only newer blocks that have serpentine setups have the possibility of a reverse flow pump ... thankfully I don't have to worry about that problem...
as for the air situation -- I agree, one will never be free of air in the system, as it is not possible to purge it all... one would think setting some kind of bleed valve or something at the highest point of flow, would do the trick???
for my truck that would be the 5/8 hose fitting that keeps popping off... every other point in the system is lower including the rad cap...
I added 2 pics of blowout aftermath #2 & 3 and one of the engine bay just beforehand...
the 3/4 hose connection I lathered in copper rtv as it was my first hose installed with these rpc hoses, and I did not trust the connection. (I did not RTV any further ones as they seemed to fit better)
it's clamped to a copper tube, no bumps on it, but the tube itself is long enough to contact both the flex hose inside that fitting as well as the tubing coming out of the heater core, so there is next to no pressure on the fitting hoses at all...
the 5/8 hose connection that keeps popping off, was first copper tubing with bumps (no pic of it sorry) second and third blow offs were this PEX house plumbing fitting, that in the second pic, you can sorta see has barbs albeit small ones, and the clamping surface of each side is roughly only that of a hose clamp wide... I've tried finding longer, but it appears 5/8 fittings are going the way of the dodo up here...
ever since nascar went to efi, the carbed sbc market has gone to the dogs...
first pic you can clearly see the inner sleeve of the RPC kit failed -- second pic the sleeve held but surely began sliding out of the outer sleeve before popping off... -- third pic demonstrates how that 5/8 hose connection is the uppermost portion of my cooling system...
I will an extra hose clamp in between the polished fitting and the hose end, and install the thermostat = if this holds, I'll be a happy guy. if not, my only other idea would be to buy some copper tubing and bend it myself, and try to swage? the ends somehow to get the bumps...