Gets hot and stalls out

George Jets said
Got headers on the car dumping lots of additional heat into the engine bay???

Have headers, yes, but same headers that have been on it for a very long time. Here are the two changes to the car in the past 2 years:

New Powermaster 95 amp alternator (old one wasn’t charging, replaced about 3 weeks ago)
.25” wood spacer under carb (done yesterday)

Absolutely nothing else has been changed on this car from last summer to current.