1970 Chevrolet Nova overheating

RSOTO89

MEMBER
1970 CHEVROLET NOVA
V8
RWD
AUTOMATIC

I got a 1970 Nova with a 383 stroker and a Turbo 350 trans. Its overheats under a load after about 30 mins. I installed an all aluminum, 2 row radiator and a 180° thermostat. The radiator is solely for coolant: I have a separate cooler for the trans. I also have an electric and flex fan on it. There is no heater hoses/heater core attached to the cooling system. The car runs great but this overheating issue is driving me crazy. The only thing I can think to do is replace the water pump with a high flow all-aluminum one. Help please!

6 Replies

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Since the engine is modified, I have to ask what you have the timing set to. How many degrees BTDC is it set? Have you checked how far the advance is going when under a load?

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Thursday, October 23rd, 2014 AT 6:14 PM

RSOTO89

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3 POSTS

Initial timing is set @ 13° at idle. Then under a load of about 2500rpm it's at 45°. It's got a Mallory distributor with an HEI cap. Its also got stock ACDelco plugs with Taylor wires. I installed a mechanical coolant gauge and its calibrated and working fine. The hottest the engine will get is about 210-220.

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Friday, October 24th, 2014 AT 12:29 PM

JACOBANDNICKOLAS

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This is a tough one. Everything is basically new. The timing seem a little further advanced than I would expect, but not that far out of line. I assume you mean 13 BTDC. This is a stretch. Do me a favor and check to make sure the lower radiator hose isn't collapsing when the engine revs. It's been years since I've see this problem, but it did years ago.

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Friday, October 24th, 2014 AT 8:27 PM

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

You know, I just re read your last post. That temp isn't really out of line when the engine is under a load.

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Friday, October 24th, 2014 AT 8:28 PM

RSOTO89

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3 POSTS

The lower radiator hose has the wire inside it to take care of any collapsing problems. I was wondering if the "normal operating" temp for that kind of motor would differ from say a daily driver.