heat issues "could" be that it was never equipped with the X fillers that 400 cars got (metal fillers between bumper and radiator, on 400 and A/C cars)also, might be missing lower air baffle, rubber(masticated)fillers at bottom and ea side of radiator...radiator could be from a 326 or 6 cyl car (but if owner has used it and it runs fine, its prob. not an issue)... also ,headers (if on it)can cause hot start problems if no heat shield is on it...also if headers are present you "could" have no back up light and neutral start issues (if missing shift linkeage, that many remove(d)(s) to clear (some) headers....
thats a few...if you DO have heat issues, lets hope not, it could be flow thru radiator, thermostat, fan, radiator size etc, many options, lets just first determine IF the car has any...
price seems fine...I paid $8k for a non matching numbers car (convert.)that needed work 7 yrs ago