47-55.1 Exhaust manifold temp

[mr48chev]

I'm thinking that you don't have a cooling system problem but possibly have an air-fuel mixture issue where some of the cylinders are running lean and the exhaust gas is hotter.

One thing is that folks with old cars and old trucks get it in their head that newer engines out of cars and trucks that normally ran down the road at above 200 degrees are now supposed to run at 170 or 180 just because they were stuck in an older rig with a mechanical temp gauge.

Ideally the exhaust should be close to the same temp on the manifold where it exits the engine up and down both banks. What temp might not be as important as balanced temp. Checked as if you were checking each tube on a set of headers.

A 20/30 temp difference between idle at a stop light or in go in or out of Vintiques traffic and cruising down the street at 30 mph is normal without some serious air flow help. Gauge goes up at a light, goes back down when you hit 20 or 30 = need more air flow when sitting still. My 48 is the worlds worse at that with no shroud or electric helper fan.