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351C engine problems

first to my car. I have a 1973 Mustang Mach 1 with an 351 Cleveland 2V and a manual 4 speed. gearbox.

I have the problem that when the car is warm it suddenly turns off. Not while driving but when i drive along and then stop for a street sign or cause of traffic as soon as i press the clutch at first gear like 10 sec later the engine turns off. Sometimes when i quickly start again to not block the traffic it runns normal but especially when the car is very warm from a long trip the engine turns off every time. So i have to rev the at about 1500 to 2000 rpm when i stop in traffic to keep the engine runing.

The engine was rebuilded 2 months ago, so i drove like 1500 miles since. I have a small edelbrock carb with 600cfm (edelbrock 1405). I have a very street use cameshaft (Speed Pro cs1085r) so normally it revs at about 800 rpm very smooth. I have a standart HEI Distributor from summitracing (sum-850025) which is vaccum advanced. At this point i was not sure but i connected the vaccum advanced port to the Manifold Vaccum Port of my carb (right port at edelbrock). The ignition is set to 8degrees BTDC.

I already tried to play a little bit with the ignition timing to set 6 or 10 degrees but nothing changed. Than i was reading that this could be a problem when the spark plug cables are crossing each other so i sepperated them with a minimum of 1inch gab everwhere to go sure but nothing changes.

Does anyone have the same problem or knows how to handle with this ?

Thanks Daniel
Its sounds like its on the spark side can you try a different coil? 
Throw some more timing at it later like 14-16, but figure out why its cutting out first.
Remember 1 train wreck at a time.
These can be difficult to track down, a lot of variables.
On the carburetor side, idle speed, idle mixture, float level, vacuum leak, fuel percolation from over heated carburetor, stuck EGR, bad fuel.
On the electrical side, coil breaking down when hot, component in the HEI breaking down when hot, bad connections, including bad grounds, timing.
Engine side, vacuum leak, low compression (bad valves), PCV valve, exhaust crossover on intake manifold too hot due to restricted exhaust on one side.

“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
As you seem to note it is heat related, I would look at whether the fuel might be boiling off in the float bowls. I'd consider a spacer under the carb like this


You can combine it with an aluminum heat shield and you will need longer studs https://www.jegs.com/i/Holley/510/108-70/10002/-1

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
There is quite a long flow chart in the Ford manual for this symptom if you can get hold of one. A systematic step by step elimination of causes. It is based on Ford equipment not your aftermarket.

When a man is in the woods and talks and no women are there is he still wrong??
+1 for the fuel spacer especially a phenolic one which will offer better heat insulation
My advice is to get a fuel pressure gauge. Install the sensor as close to the carb as possible. You need to confirm that you are getting fuel pressure when the issue happens.

73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

Pics of modifications included in:
My gut tells me fuel percolation, especially since you have an Edelbrock carb. The one piece base & bowl design is notorious for heat soaking and boiling the fuel. Install an isulating gasket or spacer and let us know how it works out.

Thanks for your Help.

I got a 1inch carb spacer out of plastic, but nothing changes. I tried it a whole afternoon but i have the same problems. The engine was very hot and i touched the carb which was hand warm. So the spacer does his job.

Unfortunately i have not the chance to get another coil or ignition system. I just can by a new one but my installed one is nearby new and when it works perfektly byside the single situation. So i dont really think that the ingnition is broken.

I dont have an EGR on my engine and i dont think the Fuel is bad. In Austria we have quite good fuel, i dont now if you know but it is unleaded Super Plus 98 octane what i get from the gas station.
First thing I'd check is if there is fuel in the carb when this happens. Maybe try to (with engine off) remove the airfilter and move the throttle to see if fuel squirts into your carb. I think will e's idea to check fuel pressure is a good idea as well. It could be heat soak (air bubble in fuel line caused by heat) and maybe the fuel pump isn't strong enough (anymore) to get fuel through quick enough.

With the engine hot, will it continue to idle if left for 10 minutes?
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