970fizz 19 Report post Posted September 27, 2014 Over the past few weeks I've changed some things on my 1969 351w. Changed the stock 4v carb to a Holley 600cfm, Holman moody air cleaner, headman short headers, 3 side exit exhaust, And now my car is overheating, but only when the car is not moving, once it starts moving the temp gauge drops back to normal. I just changed the temp sensor, but it didn't help. Thanks for any help Quote Share this post Link to post Share on other sites
ashleesmach1 28 Report post Posted September 27, 2014 those new parts would not cause your motor to overheat. do the easy first, check radiator water level. fill if needed, check for all leaks and fix. . then listen for water pump noise or leaks from water pump. do you have mech fan , clutch fan or electric fan? make they function. do you have water over flow bottle? check all hoses make sure they don't collapse. then go after thermostat and then water pump. Good luck Quote Share this post Link to post Share on other sites
970fizz 19 Report post Posted September 27, 2014 Thanks, it's a stock fan with a stock fan shroud, yes all fluids are full, no leaks. It just odd, I drove the car all august In 98-101 temp out side, with 0 problems And now it overheats every time the car stops moving! Going to put a new thermostat in tomorrow Quote Share this post Link to post Share on other sites
barnett468 418 Report post Posted September 30, 2014 (edited) hello; what was your idle timing before the changes? what us is now? are you using ported or manifold vac? try advancing it around 6 degrees as a test and see if it runs cooler at idle. you should run a stant premium thermostat a 192 might be best. . Edited September 30, 2014 by barnett468 Quote Share this post Link to post Share on other sites
970fizz 19 Report post Posted October 1, 2014 So I took the Holley 600 off and put the factory autolite 4v back on. Now it doesn't overheat Quote Share this post Link to post Share on other sites
barnett468 418 Report post Posted October 1, 2014 So I took the Holley 600 off and put the factory autolite 4v back on. Now it doesn't overheat that's bizarre, but hey, it was a cheap fix. Quote Share this post Link to post Share on other sites
jmlay 80 Report post Posted October 1, 2014 Assuming your idle speed is the same then it can only be mixture or the vacuum signal changing the advance of the distributor. How much vacuum is available on the port where the distributor vacuum advance is connected for both carbs when at idle? Did you adjust the idle speed & idle mixture, too lean will cause an engine to run warmer. Quote Share this post Link to post Share on other sites
skidmarky 50 Report post Posted October 1, 2014 Where did you have your vacuum advance hooked up? Quote Share this post Link to post Share on other sites
970fizz 19 Report post Posted October 1, 2014 I'm thinking my vacuum advance isn't working, Looks like I have some work to do Quote Share this post Link to post Share on other sites
blueblood 26 Report post Posted October 1, 2014 Had a similar issue on my 302 with 570 street avenger, was jetted very lean. Came up a few jet sizes and that brought temp down. Any chance you have a vac leak from a open port or gasket with the 600 carb? That would lean it out even further Quote Share this post Link to post Share on other sites
970fizz 19 Report post Posted October 1, 2014 I may have a vac leak as well Quote Share this post Link to post Share on other sites
barnett468 418 Report post Posted October 2, 2014 I may have a vac leak as well ok, that makes more sense. Quote Share this post Link to post Share on other sites