[drdave69]

I drove my '69 Z11 350/4 speed about 40 miles the other day for the first time and at cruising speed the temp gauge climbed to a little above center (180 deg thermostat). When idling or low speeds, this doesn't happen. I removed the radiator (original 2-row). It appears that it needs cleaning. The shop pointed out that it appears to have some high pressure leaks, so a new core is needed. I told him to go ahead and increase it to 3-row. My question - could the radiator be the only culprit?
Also, what is your thoughts on replacing the 180 therm with a 160?

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'69 Z11 Pace Car, 350/4 speed

[Everett#2390]

Keep the 180 thermostat, but buy a new one, I bought mine from the dealer, all made of stainless steel, so as not to rust.

If replacing radiator, I'd go and remove block drain plugs, thermostat housing, you're gonna change thermostat anyway, right? and flush the bee-jesus out of it, both sides of the engine. Same to heater core.

Then, to top off the job, I'd replace the hoses, clamps, rad cap, and belt(s). Might as well check the weep hole on the bottom side of the water pump for leakage, if evidence is there, calls for replacing water pump.

Now, the car is back together, and you're gonna pour in a 50/50 mix of good antifreeze/ distilled water mix. You might even add a recovery tank also, doesn't hurt.

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Everett 68/350/PG/11.90/115mph