FOLLOWING UP ON OUR SUMMER CORRESPONDENSE. I HAVE THE NUMBERS OFF MY HEADERS. THE LEFT ONE IS 3932441,FOLLOWED BY E670, GM12. THE RIGHT ONE IS 3932441,FOLLOWED BY F570, GM 9. AFTER REVIEWING ALL THE ABOVE INFO THE CASTING NUMBER COULD BE 3870014 INSTEAD OF 3970014. SO DO YOU STAND BY THE ANALYSIS THAT ITS A 1970 OR SO ENGINE? IF SO, WHY IS IT BLUE? THANKS MUCH.