302 V8 Stumbling and stalling

[67289V8]

Hi there, I hope the good Shelby guys don't mind me asking a question about a non Shelby.

I have a restored '67 Mustang Coupe powered by a stock mid 80's 302 V8 with 2300 Holley 2BRL carb.

It has a single fuel line with a mechanical pump and original distributor.

Lately and while driving in the summer heat it has been stumbling and stalling while at traffic lights and decelerating and can be very difficult start once it begins this behavior only when it is above 80 degrees or so outside temperature.

The pump and coil are new.

After sitting for 30 minutes or so with the hood up it starts and runs perfectly until it has been driving in the heat again.

It does not behave like this in cooler outside temperatures.

The engine runs at a nice 180 to 200 degrees and never overheats.

I believe it is vapor locking on the ethanol pump dinosaur pee gas.

Today I put a heat shield sleeve on the fuel line from the pump to the carb with no joy.
Any help is very appreciated! 
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[KR Convertible]

Have you tried a tank of ethanol free fuel to be sure that's the problem? 

Add a phenolic spacer under the carb or you could block off the crossover passage on the intake.  It will take longer to warm up if you drive in the winter.

[deathsled]

What about retarding the timing?  I had similar issues and was screwing around with the Pertronix module under my distributor which is a pertronix distributor and while doing so I moved my distributor. It was not bolted down tight enough.  I had to play with the distributor turning it to the point of starting and now it starts with no issues even when the engine is hot.  Maybe a timing issue. 

[deathsled]

As an addendum, I did all of the things you did, wrapping the gas line, using a phenolic spacer, even wrapping the spark plugs with those socks to keep the ignition wires cool that lead to the plugs.  Moving the distributor back (counterclockwise seemed to work).  The little nozzle tube that comes out of the vacuum will point in the direction of advancing timing (clockwise).  Retarding timing is counterclockwise.  I too have a modern 302 engine in my Shelby.  86 302 from a drag car.  Roller rockers and carbureted with a Holley 650 double pumper.

[67289V8]

Have you tried a tank of ethanol free fuel to be sure that's the problem? 

Add a phenolic spacer under the carb or you could block off the crossover passage on the intake.  It will take longer to warm up if you drive in the winter.

I am in pursuit of non-ethanol fuel but unfortunately you cannot just go down to your local gas station and get a tank full. I have been directed to a few local airports to see if I can get some there. I will be cracking open the carb to see if anything inside is out of sorts.  Will keep you posted.

[67289V8]

As an addendum, I did all of the things you did, wrapping the gas line, using a phenolic spacer, even wrapping the spark plugs with those socks to keep the ignition wires cool that lead to the plugs.  Moving the distributor back (counterclockwise seemed to work).  The little nozzle tube that comes out of the vacuum will point in the direction of advancing timing (clockwise).  Retarding timing is counterclockwise.  I too have a modern 302 engine in my Shelby.  86 302 from a drag car.  Roller rockers and carbureted with a Holley 650 double pumper.

My 302 is out of a racing boat and has solid lifters.

[KR Convertible]

https://www.pure-gas.org/

Type in your zip code and see what comes up.  I think there's more websites like this.

[KR Convertible]

You can also look for places that sell race fuel at the pumps.  They usually have it or can tell you where to get it.

I only suggested ethanol free as a diagnostic tool.  I wouldn't want to have to search for it every time I need gas.

[deathsled]

https://www.pure-gas.org/

Type in your zip code and see what comes up.  I think there's more websites like this.

^^^This!