overheats and stalls

1967 FORD MUSTANG

400 MILES • V8 • 2WD • AUTOMATIC

CHRISBENJAMIN

MEMBER
2 POSTS

I have a 351 high performance small block with 310hp the engine. It does not show to hot on the temperature gauge, in stop and go traffic the engine stalls and will not accelerate. i have installed a lower temperature thermoset and after driving and letting it sit at an idle the engine stalled and wound not accelerate. the intake gets very hot could it be some kind of vapor lock.

Aug 26, 2021 at 2:39 AM

ASEMASTER6371

✓Experienced Mechanic
52,796 POSTS

Good afternoon,

The first thing I would check is the fuel pressure.

The pressure should be 5 to 7 pounds. Any lower, it could boil causing vapor lock.

Beyond that, the carb is most likely the issue.

What kind of carburetor?

Roy

Aug 26, 2021 at 6:24 AM

CHRISBENJAMIN

MEMBER
2 POSTS

I have a Holley Street Dominator intake with a Holley 4150 650 CFM 4 barrel carb. i ordered a high output thermostat and new gasket from Holley to install to see if that helps.

Aug 26, 2021 at 7:34 AM

ASEMASTER6371

✓Experienced Mechanic
52,796 POSTS

There is no such thing as a high-performance thermostat. All the thermostats have the temperature set for opening.

I would do a leak-down test on all the cylinders and check for a failed head gasket. That is where you remove all the plugs and insert shop air into each cylinder to see if there are bubbles in the radiator.

https://www.2carpros.com/articles/head-gasket-blown-test

Roy

Aug 26, 2021 at 9:17 AM

Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.