I had an hot running issue issue forever with my 78 L-82 4 speed on the highway for 20 years. The L-82 routinely ran 225-230 on the highway on hot days and 240-245 with the A/C on. I chased the problem replacing every single component including a new brass/copper radiator, fan clutch, rad seals, timing, carb tuning, water pump, removed all emissions etc and finally got the temp down to about 200-205 on hot days with a 180 thermostat. I finally purchased a Dewitts radiator AND a stewart Stage 2 water pump and the temp would never go above 180-never.

I just recently completely rebuilt the motor with AFR heads, roller cam etc
making about 400-425 HP reusing the Dewitts rad and Stewart Stage 2 water pump-new engine. The motor has not gone over 175-180 degrees yet-highway, traffic, idling all day long. If everything is correct-timing, seals, shroud, etc-using at least a good quality aluminum radiator (Dewitts) and in my case a Stewart Stage 2 water pump-the engine should run at the thermostat setting. No need for any electric fans in a SBC, maybe a BB.

Hope that helps!

 

i replaced the heads on mine for aluminum and it ran some cooler, i can't say how much but it was a fair amount. i checked the original 882 heads to see if they were plugged up for some reason and they were clean inside.
when i added the aluminum radiator the temperatures dropped right on down.

 

I have always suspected that the hot running issues in the L-82's especially the 78-80's, had to do with the 882 heads or possibly the retarded timing these engines had to run to meet emissions, which they barely were able to achieve. The L-48's from these years did not have the high temp issue that the L-82's had and were only different in really 3 areas:

1. L-48 had a milder cam with less lift
2. The L-48 had the smaller valve heads
3. The L-48 had 8.5:1 pistons instead of 9:1 piston in the L-82.

The difference in HP in those years between the L-82 and L-48 was about 40 HP. Yes the 882's were thin castings and known to crack but the real reason the heads cracked was the extremely high water temps used to cool the heads. My 882 heads had perfectly clear water passages as well and still temps would climb on the highway (but MUCH less after all my changes).

The only conclusion is that the 882 heads due to their combustion chamber design must run very high combustion chambers that the coolant cannot adequately handle (maybe due to the water passage design). The only other issue I have noticed is that the exhaust passage under the intake manifold for the EGR valve is mostly blocked by the Felpro intake gasket with just a small hole to allow the exhaust gas to pass from one to the other (less than a 1/4 inch hole in the gasket). Possibly the exhaust temp from the 882 combustion temp is MUCH higher than from the fast burn AFR heads). Thoughts?

 

without question timing was a big factor.

 

True, but even with the "correct" timing, my L-82's temp would still RISE on the highway with speed and revs instead of fall. Of course, with 3.70 gears and the 4 speed, turning 3,500 RPM's all day on the highway versus 2,500-2,600 RPM with some of the autos especially in the L-48 would muddy the temp issue.

 

I hear that a lot, but have never seen any kind of apples to apples proof, not that I'm saying it isn't the case.

 

ask Lars, timing being retarded causes the engine to run hotter.

 

I completely agree with that being ignition timing, my dumb not awake *** was thinking cam timing, not ignition timing so my bad.

 

Pulling the stock radiator hopefully tonight and buying the aluminum radiator tomorrow after work. Will bring the old one to line up against the new to check fit and alignment.

Thank you for all of the input.

 

Is there a market for a 4 core radiator? I may be willing to sell my old radiator.