1) I shut it down at 240 last night but it has gotten up to 250 and boiling over. The gauge works properly, the fans are suppose to come on at 190 and as soon as the gauge hits 190 they come on.
Gauges look good...
2) See above response for fan flow, it is advertised. Good test, left fender meaning drivers? My original one did not have a clutch.
Yep, drivers fender, hood up. The stock rigid mount fan should have had a similar output. Any debris between condenser and radiator (assi=uming you have A/C?
3) My guess, never. I have never done it. Block plugs? You mean freeze plugs? How would I pull those?
Nope, Two 9/16 inch hex drain plugs - just unscrew 'em. At the front of the block, above the oil pan, one on each side. If the engine is dirty, they should be under a bunch of muck (like my 350's were)... I assume the 69 455 would have similar plugs???
4) I am confused on what you are trying to tell me here "The stock water pump should be able to maintain 192. Simply cutting
power to the electric may then just cause a restriction."
Sorry, I seemed to have deleted a line or two that stated, try to bypass the electric pump to make sure the flow is not TOO fast. Cut power to the electric and totally bypass the pump with a hose coupler.
5) Yeah, at the most the rad is a year old. With changing everything 100 times I have yet to see any signs of crap coming out of the cooling system.
Simple flushing will not remove most hard water deposits or corrosion.
Try just water & 2 bottles of the prestone super cleaner, run for 8 hours, then drain, backflush with water. Back flush radiator with a hose and the block, too, with the block drains open... I saw a big difference in my rad by doing this.
6) Timing that is a good questions. It was set this last time when I changed the cam but the timing plate has three marks. I guessed and used the middle one (I think), So let me ask you, did I time it right? The vacum was off when I timed it, that is correct? I am going to check compression on each cylinder and vacum some time this week.
Vacuum hose disconnected and plugged - correct. set timing per vehicle spec. (I do not know off hand what the 69 455 needs. The middle mark on the 72 is 6*BTDC.) Check into this.
----Did the overheating start just after you changed the cam??
7) Vacum advance, how do I check to see if this is working correctly?
Disconnect vac hose from disty and plug hose. Run long clean hose to disty vac advance can. Start engine. Idle should be lumpy. Suck on hose. If RPM changes, it should be doing something. Suck on hose with timing light on pointer - mark should appear to move (poor man's quick test).
8) How do I check fuel mixture without a gauge?
Not sure if a gauge exists for this... Pull a spark plug or two and observe the color. Blistered white or grey insulator by tip indicate too lean. It should have a light coffee brown color to it. Black soot is too rich. Oily is oil leakage.