From the perspective of stock LT1 engines, you may not think I had a problem. My '92 383 stroker LT1 was running about 205* at highway speeds, and idling at about 190*. However, those same temperatures persisted in the New England winter, and the heater was hardly putting out any warm air this winter. A few years ago, the water temps were much lower and the heater had plenty of oomph. Hmmmm.

I was afraid that both the radiator and heater core were fouled and possibly shot (both original). With almost 19 years on the car and over 160,000 miles, that wouldn't be surprising. However, last month my mechanic heard some whine coming from my 3-year old Meziere electric water pump, so he swapped it out for a new, higher capacity pump (55 GPM instead of 35 GPM). Unfortunately, the water temperatures remained unchanged.

Today I fixed the right part - the thermostat. I had a 160* t-stat installed about 5 years ago, and recently it wasn't opening properly. 10 minutes of work and a new t-stat was installed. Now, cruising at highway speeds, the water temp never rose above 178*, and quickly dropped to 173* at city speeds. At idle, the temp hovers around 171*.

I don't want to engage in a pissing match about how the LT1 prefers to run at 220* and higher. Whether or not that is true for stock engines is irrelevant. My engine is built and tuned for quarter-mile performance, and I have reams of timeslips showing that it runs at least a tenth second slower if I start the run at 185* compared to my target of 170*. Even more important is my ability to start with a consistent water temperature, in order to have consistent runs in bracket racing. That's why I have the electric water pump and manual fan switch - so I can cool the engine between runs quickly.

Cliff's notes - fixed overheating engine by replacing the tired thermostat for a new one. Color me happy.