1966 327/300 exhaust manifold question

[Jeremy B.]

Are the exhaust manifolds on a 1966 327/300 with K19 A.I.R. the same as those without K19 A.I.R., but with the ports plugged?

[John H.]

Re: 1966 327/300 exhaust manifold question

Are the exhaust manifolds on a 1966 327/300 with K19 A.I.R. the same as those without K19 A.I.R., but with the ports plugged?

Jeremy -

No. The K-19 exhaust manifolds (casting #'s 3872765 and 3872778) were drilled and tapped for the air manifold tube nuts; non-K19 cars used different manifolds (casting #'s 3846559 and 3747042) that had no such provisions.

[Joe L.]

Re: 1966 327/300 exhaust manifold question

Are the exhaust manifolds on a 1966 327/300 with K19 A.I.R. the same as those without K19 A.I.R., but with the ports plugged?

Jeremy------


No, they are different castings although the GENERAL configuration is the same. The reason for the different casting is that the non-K-19 manifolds have no bosses for the AIR fittings and the K-19 manifolds do have such bosses. For the 1966 model year I know of no application that used manifolds with the AIR fittings that were plugged with pipe plugs.

So, why didn't they just use the same manifolds for both K-19 and non-K-19 applications but without the bosses drilled and tapped for non-K-19? Well, they could have but they didn't. At least they didn't for small blocks. For big blocks, they did----the K-19 and non K-19 big block manifolds used the same castings for either but with the non-K-19 not drilled and tapped for fittings (except for some 1970 LS-5 which did use manifolds with fittings and pipe plugs).