:=ok guys ive got a real puzzler for yall, ive got a 74 mav with a 250, and lately its really ran like crap. ITs symtoms are dieseling (running after engine is off) and terrible smoking and exhaust leaks. I narrowed the problems down to either timing chain is stretched or bad valves.( note the other day when my engine was smoking i cheked it out and the exhaust manifold was bright red and loo0ked like it was aboout to melt) so im at my wits end trying to find the problem. And ive also noticed a great loss in power, this might be due to the exhaust leaks witch will be fixed this weekend. I apprieciate your help.
:= Jimmy
............................
Jim, if the engine got that hot, there is likley more damage. Very late ignition timing will show up this sort of result. The larger part of combustion is taking place too late in the cycle with the exhaust valve open is why the manifold got so hot. The exhaust valves being so hot is igniting the new charge instead of the spark plug and of course the power will be way down do to the loss of cylinder pressure. Don't know what happened but you nearly have to start over again with the engine to see what all is wrong.. Know you don't want to hear that but!
Best of luck,Ken