My question is this, My car has been in long storage. Upon restart a tremendous amount of white smoke was being emitted from exhaust. My center exhaust port headers glowed red. After awhile the smoke subsided. Car will not run without a lot of backfiring unless revs are kept very high. Checked all the normal things, timing, carb, air leaks spark plugs all look good, etc. Overtime I restart car same thing. Could this be caused by leaking cylinder head gasket that is resealing itself upon engine heating up?

I drained the gas tank and put new gas in tank. Also cleaned the carb by removing, taking it apart. It isn’t a gas issue.This isn’t a one time event. It always happens when I start engine. Glowing header (center 2 exhaust headers) and it lasts about 5 minutes before it clears up. But still backfires unless revs are very high. Thank you

I do not think I have a heat riser.

No, There is not a heat riser. When you cleaned the carbs, I presume still has 2 SU's, did you make sure pistons moved freely and put machine oil in the reservoirs? You may just have carb problem. Also, in just sitting, you may have a stuck thermostat. (Nothing to do with backfire but should be checked)

Check your valve adjustment while you are at it. Use a good fuel system cleaner, check the points and set the ignition timing.

Doing a compression test and re-torquing the head can't hurt.

Keep in mind that the center exhaust pipe gets twice the heat of the other two.

Still strange that it gets red hot! Maybe lean mixture. Still think it is a carb problem.