Overheating at WOT

Hey guys, I am currently dealing w/ the consequences of throwing together a motor that a friend had laying around and thought I'd bug you guys for some advice. It's a high mileage 71 440 that we threw a cam in. Stock top and bottom end except for cam, lifters and springs. Comp cams xe-268. It was out of an imperial and was obliviously babied. Clean bores, doesn't smoke or make any noise. We pulled the heads and replaced all the gaskets along with the oil pump, timing chain and cleaned everything in the short block as best we could. The motor is in my 65 belvedere 2 and has the original radiator tanks with a new 4 row core, milodon water pump, Chrysler viscous 7 blade fan, 65 stock shroud and. 160 degree thermostat. It has the heater deleted. It will sit and idle at 190 forever but when you take it out and beat on it, it heats up quickly(220 and climbing on a hot day)and slowly will cool down as long as your still moving. The carb is an eddy 750 and it has a Firecore distributor. Timing was set until it pinged and then backed off until it stopped. My(long-winded) question is, would this be due to the cam making the motor run lean? Again, it will stay under 200 until you open the throttle all the way. Would this be indicative of the timing being off? Thanks for any ideas!

or a bad rad

As to lean vs rich, read the spark plugs.
In addition to radiator/thermostat/fan clutch/shroud, two things come to mind right away:
1) lower hose could be collapsing
2) you absolutely did use a degree wheel to verify indexing of that new cam, right?

J

The Horvaths said:

As to lean vs rich, read the spark plugs.
In addition to radiator/thermostat/fan clutch/shroud, two things come to mind right away:
1) lower hose could be collapsing
2) you absolutely did use a degree wheel to verify indexing of that new cam, right?

Click to expand...

Good idea on looking at the plugs. I will do that soon, radiator is new and lower hose has a spring in it. I guess my question was, IF timing and/or being lean were the cause of the overheating, then would it make sense that it heats up under WOT or would it run hot all the time? Thanks guys!! Sorry for the long post!