overheating issue

[twoskies]

hello

1972 c10 350/4 bolt main

aftermarket 4 core radiator, had a heating issue, was not very warm, tried just changing thermostat to 195, seemed to help, then fighting a leak at housing, well 2 housings later and several gaskets
i cleaned the original housing and manifold, took a file to both to just clean , gasket sealer on manifold, felpro rubber gasket, and wait 24 hours (patiently/not)but did wait 24 hours, good thing, no leaks

bought a funnel system to burp air out of cooling system, also seemed to help, although the temp guage showed slightly higher, took truck for a drive and guage doesnt peg all the way but goes to 1st mark on right and drops back

any help appreciated