I have three 1.20R's and a 1.20 but I do not remember seeing a gasket on the exhaust flange. They sort of just screwed in until the exhaust pipe lip butted up against the head tight.
You might consider sending your head to Clarence Lee to get a new insert installed for the exhaust. It could either be the threads are worn and loose now or the threaded exhaust flange is worn instead. Of course if it is holding up OK and not coming loose, maybe some high temperature silicon gasket sealant will do the trick and seal it up. You could also fabricate a fibre or copper washer to fit inside and see if that would do it too.
I think I have accumulated a number of Enya engines over the years too.
three 1.20R-4c a 1.20-4c a 80-4c a couple of 60 4c and a couple of 46-4c if I remember right. Plus a big Enya 1.55R-4C as well.
I have a bunch of the other Enya's some .15's, .19's, 29's, .35's, 40's, a 45 maybe, and a .50 as well as a .61 too.
I also have a cute little .11CX diesel too.
Last edited by earlwb; 10-18-2013 at 10:04 AM.
Reason: add more information