I certainly trust you buddy, but we have a puzzler to solve here. I have some 670's that share the 272 plug angle. They are single coil saws from 92 and 97. I have an additional cylinder that I installed on a 1987 625. It also has the taller plug. As does a 1992 625II. My guess as to what's going on here: There are early and late 625 and 670 cylinders. (630 remained the same throughout it's run). What I remember is that they went to a longer "neck" on the intake port when they switched from the wire boot clamp to the band style clamp. (And the intake boots were also changed). Could they have changed the plug angle at the same time? I really don't know and I don't have any of the early wire clamp cylinders to look at. So, you're going to have to clear this up my friend.
On to the top covers themselves, The cylinder cover really doesn't matter here. The later air filter covers all have a bigger spark plug hood, including the 630 even though it's plug angle never changed. The new filter cover will fit the early cylinder cover. Of course none of them are available so we have to make do with what we have. My 625/70 has the old filter cover and while there is that unsightly 1/4" gap because of the poor fit, it more or less works. The advantage with the 2 piece Jonsered set up is that the cylinder cover can still be secured properly.
Still the most fun chassis project wise for me. Another home grown model I built is a "636 Super". Used a 50mm 266XP cylinder on a 1985 630. 266 has the same plug angle as the 630, and requires zero changes to the intake. Same intake block, gaskets. Gonna run that one tomorrow.
