Note the outlet id just a little smaller than older manifolds.

How can you tell ID just by what you posted?

Says who?

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Manifolds with this number 4100448 and dates 79,86 and 95 1 and 15/16 outlet. 2 manifolds with this number 4027567 from 1977 and one manifold with number 8 or 3 671882 from 1973 had 2 inch outlet.

Is 1/16 difference in a cast iron exhaust manifold inner diameter intentional or manufacturing tolerance? Maybe some of the older cores were wearing out and resulting in a slightly smaller inner diameter?

This kit comes with instructions,

Last 4267233 I measured was a good number of years ago, but I recall it being the same as the '65 manifold I was comparing: 2" even.

In any event, if you encounter one with a 1-15/16" outlet, take a cylinder hone to it and get back your 2".

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.