Join Date: Jul 2004
Location: Fountain Inn, SC
Increased power and/or lean mixtures will create more heat that has to be transferred through the radiator. A stock radiator in good shape should be good for at least 150 HP with correct mixture. My radiator became marginal when the power got up to about 170 HP.
Reading through your thread, it looks like you replaced the head but I did not see any mention of performance oriented changes. Is that correct? Is there a reason you would expect the carburetor jetting to be incorrect? I recently saw a temperature increase of 20 degrees F after significant engine changes and before increasing the idle jet size. This was during the 30 minute cam break-in process. I am running emissions Dellortos (DHLA 40L) and changed from 57 to 65 idle jets, which brought the temperature back down to 180 degrees (and eliminated spit back).
'65 Sprint GT, '78 Spider, '88 Quad