Hello, I have a 1976 245 w/B21F. The exhaust manifold seems to be running very hot. I have measured it at about 450ºF. First, is that too hot? I don't ever remember it being so hot that it makes the shock tower almost too hot to touch.

I don't think there is a restriction in the exhaust system. It does NOT have a catalytic converter. The exhaust blows hard out the tail pipe. I have richened the mixture so much that you can smell that the engine is running rich. I took out the spark plugs and none of them are burned and they look like it's been running rich as well.

I checked the manifold temperature on one bank of my 3.8L V6 Cadillac and it measures about 420ºF. Someone told me that you can expect about 150ºF additive from each cylinder. I've had the car since new so I'm pretty sure it has not been this hot in the past.

Any ideas? Thanks, John Crabtree, Simpsonville, SC