Valve Seal Question

[dwbarracuda65]

New to the site but have been reading posts for a while, time to tap the knowledge. Working on a set of 318 HP heads 1.88/1.60 bought a Fel Pro engine gasket set and it had 8 of one style valve seal and 8 of another with no instructions. Can anyone tell me which is intake and which is exhaust? I was also wondering if anyone knew what it normally cost to have the heads machined for the positive seal type.

Thanks.

 

[moper]

the shield on the left is exhaust side, the positive rubber one on the right is the intake.