He doesn't block the exhaust crossover in the intake? Makes it warm up faster. Most people think it gets too hot and causes vapor lock.
Yes and up here in Michigan summer is over already. High mid 60's today. After a a drive the carbs are cool to the touch from all the cool air going through them. Seems like only in very warm weather 80+ that intake exhaust heat is too much, most other times its more helpful than harmful. Raw unburnt fuel will wash away the oil for the piston rings and cause higher amounts of wear.
On WOT in cool weather the air goes through the intake so fast it does not have much time to heat up.
Now if I lived like in say Texas, I would block the intake exhaust heat.