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corvette overheat

genog

New member
Joined
Aug 15, 2019
Messages
1
Location
texas
Corvette
1967 corvette coupe
corvette_1.jpg
I have a 1967 corvette 427, which is overheating. it has 11-1 pistons chevrolet alu .heads. Timing was set at 5* with no vac advance. I think I have series head gaskets. I have installed a 4 core alu. radiator with twin electric fans (3100cfms). (pulling thu rad). Also installed a high flow water pump. What is next?

Geno
 

Hib Halverson

Technical Writer for Internet & Print Media
Joined
Jan 10, 2001
Messages
13,453
Location
CenCoast CA
Corvette
71 04 12 19
First, describe the symptoms which make you feel it's overheating.

Does this happen when you are running the engine hard? Does this happen when you are cruising on the highway at 60-70-mph ? Does it happen in around town traffic at lower speeds?

Have you tried reinstalling the vacuum advance?
 

Gerd_W2ISB

New member
Joined
Aug 17, 2019
Messages
1
Location
Inverness, FL
Corvette
2019 Z-06 Covertable, 2004 White Coup
I'm a 60's 70's drag racer and was skilled in ignition and carburetion. You can run into overheating with both under and over advance situations. My '69 Z-28 Camaro ran best with 16 deg. initial timing and 36 to 38 degrees total timing... all in by 2,600 -2,800 RPM. the vacuum advance was very limited to probably less than half stock and coming in late rather than early. I don't remember how many deg. I limited to but it was very limited with the higher initial and quicker curve on the advance.

5* initial with no vacuum advance is seriously retarded timing. If I remember correctly the big block could handle pretty much what the small blocks could. Set that distributor up with 12 initial and 36 total for starters at 2,800 RPM, maybe bump it up 2 deg. from there. Take you vacuum advance arm and limit it to less than half its normal travel, or find an adjustable one and go from there. You probably will need a shop with a SUN distributor machine... must be an antique by now.

Good luck and have fun... keep the octane up!

Gerd
 

LLC5

Well-known member
Joined
Sep 28, 2004
Messages
2,299
Location
Wa.
Corvette
98 black 6spd convert.
What temp in degrees Fahrenheit are you referring to as overheating?
 

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