Hi guys. Im gonna hit the junkyard soon and I need some help. I currently have some swirl port heads on my IROC. So I wanna drop in stock 1987 IROC 350 heads. I asume the IROC heads flow better than the swirl intake heads. So here is where I need some help. Here is a list of 350, 1987+ 350 heads. Which one is our 87 IROC heads? What is the casting number to your 87 350 IROC heads? Any help would be perfect. Thanks guys.

10065202 1987-95 350
10065203 1987-95 350
10065204 1987-95 350
10065206 1987 350 1.94 1.5
10065206 1987-95 350
10159550 1987-95 350
10159552 1987-95 350
12506450 1987-95 350
12516852 1987-95 350
14089119 1986-88 350 1.94 1.5
14089119 1986-88 350
14094093 1986-88 350
14094093 1986-88 350
14101083 1987 350 1.94 1.5
14101083 1987-up 350
14101128 1987 350 1.94 1.5
14101128 1986-87 350
14102191 1986-88 350 1.94 1.5
14102191 1987-up 350
14102193 1986-88 350 1.94 1.5
14102193 1987-up 350
3901068 1987-up 350 64