Strange Canadian SBC head

Years ago I bought an ***orted lot of dis***embled small block chevy's. In the lot there was a 283, 327 and 350 4 bolt block, cranks and cams for each, and two sets of cylinder heads. One set of heads had casting #3814480, which is a 283/327 from 60-67 1.72 intake 1.5 exhaust 70cc, so not an amazing or rare head, just an old regular from the looks of it.

The other pair has me stumped. It has an irregular casting number, 8786886

It has a weird triangle of letters A
D N

CANADA GM2 on one head, CANADA GM1 on the other.

Any idea what the heck these are? Thanks!

 

I couldn't see the picture....kind of hard to spot something if you can't see it....???

 

Judging by the detailed photos, I'd say you might have a pair of truck heads.