overheating

[Dick Simon]

I recently rebuilt my 327ci 365hp with 11 to 1 compression pistons in my 1965 corvette converable. When on the highway reving 3000 rpm's or higher the engine will overheat within 10 miles. Driving around town the temp. is fine. The raditor is about 15 years old and seems to have good water flow. Before the engine was rebuilt the old rad. kept the engine cooled off fine.

People have told me to install a big block raditor or a new griffin raditor.

Any ideas?

Dick Simon fuzzycindy@netzero.net

[Gary S.]

Re: overheating

Dick, I had a similar problem with my 66 350hp L79. I could drive around town all day and never overheat. On the highway there was enough heat generated by the engine that the 33 year old radiator could not keep up with it and it would overheat. I tried every item to see if I could get the temps down. Once I put a repro Harrison radiator in the car, my heating problems were over. I don't know what type of radiator you have or what your original compression ratio was but perhaps your radiator is tired. I am assuming that you have checked the obivious things like timing, hose collapsing, etc. Gary 21316

[Craig S.]

Re: overheating

Dick - my 67 L79 KH car has the same symptoms - around town, it runs reasonably cool, get on the highway, and it is subject to overheating. In town, with the AC turned on, it will overheat at lights, and on the highway, well, you get the picture from the comments above only moreso. I put in a "correct" 7 blade fan, which did improve the cooling some. By exchange of some notes last fall with Pete Lindahl, I have come to realize I need a 5 blade fan, versus the "correct" Paragon repro fan, to be right, as the 5 blade fan on my car Pete helped identify as a C10 1966 pickup fan that is also 18". Now I have a DeWitts repro radiator to replace my original 1972 service dated Harrision, which I am sure is the core of my heat problem. I drive the car some, and, living in Tucson, as you can imagine I need all the cooling healthy. Glad to hear the DeWitt worked well for you on the cooling front.....Craig