454 Running Hot

down home wrote:
First thing to check is radiator and air conditioner,and clean out with low pressure pressure washer and soap while warm.
Second you may have a thermostat stuck part way closed. Install a new normal open, when hot, then flush cooling system and check for collapsing hoses and fresh antifreeze. Look around the head surface engine block joint and wipe with cloth and see if there is antifreeze. Check engine oil for level and smell and color and foam of oil or oil like substance floating when you take the cap off, cold. Check the plugs for one or two for signs of antifreeze or oil. Run a compression test and watch for bubble in top of the radiator.
Engine noise possibly? Did you use 93 octane or 87 octane. High loads, even in low octane spec engines can raise temp and even detonate. 93 octane may be required. I'm betting on clogged fins and possible stuck thermostat or clutch fan not operating soon enough.
Let us know please

Thanks...I don't have cab A/C so I don't have the issue of junk collecting between the condenser and rad. The thermostat is new, but I think it might be too hot. EDIT - it's a 195 thermostat from Autozone that has mixed reviews. I'll replace it with a 180. The engine is solid - it's a low mileage unit. I did a compression check before I put it in and checked for leaks. I've put about 600 miles on it so far. Oil looks good. I use 87 octane. It's not detonating as far as I can tell. I need to check the timing as I think it's a bit advanced.

I think I'll have the radiator re-cored. I've had them done on other old vehicles in the past with good success. Won't have time to do it before my next trip out, but I'm hoping some of these other steps will keep it cool enough.