Determining the year of my KA24de

[t-rex001]

I bought a 1990 240sx. The guy I bought it from got it out of the junkyard. I know from the vin it is a 1990. Now the weird part is that has a ka24de in it. I also own a 1991 240sx with the original motor in it. I noticed that the valve covers are different, making me think the motor in the '90 is from a 1994-1999 (s14) 240sx. Does anybody know of a way I can tell for sure what year the motor is.

[DALAZ_68]

if the motor has a center rear bolt on the back of the valve cover...then its a OBDII KA

OBI didnt have the bolt...

thats the best way to determine if its an OBDII right off the bat