Red Hot Exhaust Manifolds

[earlroots]

1985 chevy G20 5.0L 4bbl quadrajet 3 spd trans.
ok the thing bogs under load and pops and exhaust comes out the carb. i did plugs wires cap rotor wires and fuel filter. then drove it with the doghouse off and noticed the top of the Y pipe and both manifolds getting cherry red hot. so i figured it was a plugged cat. replaced the cat and the problem is still there. i cant check the timing because when i unplug the 4 wire connector the thing won't start. when i unplug the 4 wire con. while van is running it dies. as of now i am stumped i have never seen manifolds get that hot before without any exhaust restriction. any suggestions??

[Evil Result]

sounds like your timing has been retarded to the point where the spark goes off while the intake is still open... or mabey somehow a stuck exhaust valve. mabey at the overlap point on you cam shaft could explane why both exhaust come out of the carb and red hot manifolds, although i'm not shure.

[curtis73]

Agreed. Check the timing... its OK to do it with the wires plugged in, just not as accurate.

Its also possible that the manifolds glowing and the popping are unrelated. My 1996 Impala SS manifolds glow pretty nicely in the dark.

Its also quite possible that the fuel system is not quite right; fuel pump, acclerator pump, filter, or dirt in the carb... all of which could cause a lean condition and account for both the popping and the hot manifolds.