A.I.R. plugs

[pjbizjak]

What type of bolts were used to plug the AIR holes in the exhaust manifolds.

[JohnZ]

What type of bolts were used to plug the AIR holes in the exhaust manifolds.

They were special hex-head plugs, P/N 3889330 for small-blocks, and P/N 444618 for big-blocks - Rick's has them. They were only used on units built for overseas export, as part of RPO KD1, Less Air Injection. The plugs were 1/4"-18 National Straight Pipe Thread (matching the threads in the manifold holes), NOT 1/4" NPT tapered pipe thread.

[pjbizjak]

Well now I'm wondering if my 'Z' was an overseas unit? I bought my 68 'Z' in 1970 and it didn't have the smog equipment on it and the manifolds were plugged. Any other way of telling if it was a KD1 unit?

[JohnZ]

Well now I'm wondering if my 'Z' was an overseas unit? I bought my 68 'Z' in 1970 and it didn't have the smog equipment on it and the manifolds were plugged. Any other way of telling if it was a KD1 unit?

Highly unlikely that it was an overseas export unit if you bought it here in 1970; LOTS of Z's (and other cars with A.I.R.) had the smog parts removed immediately after delivery back in those days.