Help 351w overheat

[970fizz 19]

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

[ashleesmach1 28]

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

[970fizz 19]

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

[barnett468 418]

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

[970fizz 19]

So I took the Holley 600 off and put the factory autolite

4v back on. Now it doesn't overheat

[barnett468 418]

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.

[jmlay 80]

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.

[skidmarky 50]

Where did you have your vacuum advance hooked up?

[970fizz 19]

I'm thinking my vacuum advance isn't working,

Looks like I have some work to do

[blueblood 26]

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

[970fizz 19]

I may have a vac leak as well

[barnett468 418]

I may have a vac leak as well

ok, that makes more sense.