My understanding is as follows. 240 turbos were not factory intercooled until 1983 (maybe '84?). People who owned '81-'82 models could return to the dealer beginning sometime in 1983 and get the dealer installed kit. I've got the receipt for when this was done on my '82 245T and I sem to remember it cost something like $2K back then.

740s and 760s were all intercooled from the factory. They dropped the "intercooled" badge from the back of the car sometime around 1990, though the cars will still intercooled.
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Nineteen Volvos
445-544-122-1800-240-740
Four turbos