i recently purchased a 1966 chevelle ss convertible from the desert in cali
the car sat there for over 25 years
it is all original
when i pulled the 396 motor out it is a 961 block but it is stamped twice a 375 hp code and a 360 hp code
it has 325 heads on it
and also the sequense # does not match any sequense #'s in that year or other years
is it a true gm screw up from a special order car
original 24,000 miles

lol you may have a rare find there. Also from the car being desert kept, is there little rust?

could be replacement engine under warrr. or ? are pistons flat with vale relief or do have ring around out side 2 or 4 bolt main sounds like a mix of pieces check the cam cast # or crank cast # and rod # in cast # book are heads round or ovel port hp were ovel check cast # copo cars wre unusal but did exest email me for more info gm mussle cars are holbby