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BBC. China MAP Replace with Delco/GM. in BBC and others under load, Fuel will WICK up the Vac tube. Contaminate the sub-strait of the strain gauge. This shifts the MAP output voltage and the engine runs very lean/LEAN mixture. (No Codes set either back in those days) So lean the EGTs will be over 1600 Deg. Ex Valve grow longer or tulip, then engine destruction. Remove MAP. Place white cloth/Kleenex on palm, Tap vac inlet of MAP. Any liquid of any kind is shifted lean.)
Insure MAP is manifold Vac. NO LOW POINTS IN MAP LINE. Install MAP at the top of the firewall run vac line, no sags, to Manifold vac.
That would certainly explain the high EGT and glowing exhaust manifolds. It has gotten so hot that wire loom has deformed. New Delco MAP has been ordered.
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BBC If you live in the frozen tundra keep the thermac active in temps starting at 48 deg F and lower Esp on humid days. Stops TB Icing. If not in cold, run the thermac Vac line plugged so thermac is INOP 100% & remove hot sir tube. In MI I never had any iced TB with any carb/TBI BBC. Run air cleaner housing intake tube to Rad support as Suburbans. Helps when under hood temps are Very hot during loads. Use Small Block Large Truck air cleaner TOP. Use Large A/C Filter. (#753? vs #248) Double air flow. BBC needs cold air. In some cases VE may need to be touched up. (Injector pulse width at low %. With higher fuel pressure it is difficult for the Injector to overcome the pres and begins to be unstable. Physics)
While most of the year here in AZ we are warm, we do get a few weeks/month where we are in the 20's overnight and 50's during the day. I'm not ready to remove the coolant flow through the intake just yet. I do have the factory cold air tube in place which is routed to the radiator support. I've been looking at a dual snorkel setup from RamAirBox, but that is a project for later.