Bit of vapour lock maybe?

 

I think I've read on here that the ICM (Ignition Control Module) acts up when hot, and when they fail you certainly get a "Cranks But Wont Run" prob.

Starter - Unlikely imo if your engine cranks.
Battery - Unlikely imo if your engine cranks.
Battery to starter cable - Unlikely imo unless it was damaged.
Ignition cylinder - Unlikely unless you got no response at turn of key.

***Ignition switch - Did you mean ICM? If so, was it new or used and was it tested prior to installation? Please ensure you have fuel & spark...

 

When this no-start occurs, does it have spark at the plugs? Does it have sufficient fuel pressure? Are engine-to-chassis grounds secure? Don't throw more parts at the car; do some basic troubleshooting.

 

 

Ignition control module

GD

 

 

This sentence causes me physical discomfort...

 

when it refuses to start, spray starter fluid into the carb or a bit of fuel. if it refuses to light this mixture it's likely a spark issue.

if you're running the original distributor it would be worthwhile to inspect it carefully under the rotor, or just replace it. A new dist will come with a new ICM, for not much more $ than purchasing an ICM alone.

 

Kids on phones. No punctuation or capitalization.

 

Are you sure its carb and not a throttle body injection system?

If Carb are you running an Electrical or mechanical pump? What is the engine out of (I don't think you could get a 350 in 85)

Before you go replacing parts, pull a spark plug and have someone turn it over during a no start situation and see if you are getting spark, and note the intensity of the spark. Also note the condition of the plug. ICM, Distributor, coil, or other ignition issue should be observable as either no spark, weak spark, or spark not hot enough (color of spark).

You can also buy an inline spark tester for a few bucks that goes between the wire and the plug or the cap and the wire. Being a carb it should be easy enough to diagnose. I'm assuming the float bowl is full during this situation, if it is that would be a indicator that you don't have full vapor lock. If its empty you may have a float that is getting stuck at the top or some other issue there (I'll let the carb gurus chime in if that is the case)

Just note its not too uncommon to get a bad ICM from the parts store also make sure you are using the thermal compound and have it mounted tight (and have cleaned the surface)