If you don't have a temperature gun buy or borrow one and verify the temperature gauge is reading accurately (especially if it's an electric gauge). I've run into a couple over the years where the only problem turned out to be the gauge.

I agree with what 36 Sedan says and that should probably be your next step..

If that doesn't completely cure the problem here are a few other things that will probably help. I fought heating issues on my 58 Chevy for the first couple of years I was driving it. Changing fans, the radiator and a few thermostats it turns out the problem was air was backing up in the engine compartment (I had installed the factory control arm seals when I built the car. Removing them to allow the air out cured the problem.

Aftermarket electric fans are also not my favorites. A lot of guys seem to have better luck adapting factory electric fans to their projects but the down side is they usually take up a lot more space than the aftermarket ones. My own personal preference is a factory 7 blade fixed fan on a thick HD fan clutch with a good fan shroud.

If push comes to shove you might also look at a different radiator. I bought one of the 4 row champions a few years back. The problem is the tubes are usually only 3/8" wide, which gives you about 1 1/2" cooling surface as opposed to 2" with a 2 row with 1" tubes. I ended up replacing the 4 row with a Champion 2 row (1" tubes) (same physical size) and the temperature going down the highway dropped 10 degrees.

Rather than completely revamping the cooling system all at once, (as my last suggestions would require), do one change at a time and see what works.

As Denny says pictures would help (and besides I'd love to see that 348).


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