what 454 is this?

[XXXGoldL34M20]

my friend has a motor running in his car and wanted some help in finding out what 454 he has. the pad in front of the passenger head is decked so no numbers there.
Casting at the back of the block by the bell housing is 3963512 K-7-9 which is a 454 dated November 7 1969.
now there is a Vin# on the pad near the oil filter which reads 10S189855 which breaks down as 1=Chevrolet 0=1970 S=St.Louis and 189855 would be the Vin# to ?
is this a 454 for a corvette or impala and if so what horse power rating is it.
the top end has a low rise GM aluminum intake with Hi Horse Square port heads but it does have the smaller oil pick up hole so i am guessing it is a 2 bolt main with the hi horse top end installed.
judging by the Vin# it is to high to be a corvette 454 so maybe it is a impala 454. what was the difference between the 390 HP vs. 345 HP 454.
any help appreciated.
attached is a photo of the Vin# by the oil filter.