454 decoding

i have a 454 with casting numbers 3999289 on teback of the motor it also has a letter p turned towards the flywheel under the casting number in themiddle of the back of the block is K12 73 on the front pad below te alternator is T1128TRT and C4F137975 as bet a i can find this motor was in a1974 truck but i would lik to know for sure and if it is a passenger block or a tall deck i dont have another to measure widts of intakes to compare ay help will be appreciated yu can e-mail me at denver70@hotmail.com thx

3999289....454.......71-79...2 or 4 bolt, some "CE" replacement blocks had four bolt main caps

Passenger block.