340 with edelbrock heads overheating
hmmm, ok yeah increasing the timing just seems like too easy a fix lol-
Well, my dad's 440 was getting hot a cruise on a flat road at 80 deg F outside temp going 65 mph, it would creep up to and over 210 deg F. This is in a 66 Coronet 500, 4 speed, 3.91:1 gears. .040 over 440, 4th largest Voodoo cam, ported 915 heads. He has a 3 core Champion radiator and fixed fan, no shroud. He was ready to buy an even bigger radiator and I told him don't, see if it's a tuning issue first. He has a Holley 870 Avenger. I said kick the initial timing up to 18 degrees (he was at 16) and give the idle jets about an 1/8 turn and go for a drive. First drive it crept to 195 and stayed. He gave it another 1/8 turn and goes to 180 now under the same conditions.
So small easy changes, big difference in outcome.
But, you should also check the rest of the system as other have noted to be sure they are correct too. Pulley size, spring in lower hose, pump capacity, thermostat flow (there are high flow thermostats too), etc.
My 340 wants 28 degrees initial with aluminum Speed Master heads and would probably take more. Any less and it would bog coming off the clutch. Mine stays at 180 Deg, hot boxed in my garage tuning on it.
