That 8 might be a “B” on the Purolator filter. I’ll look at the number again and see if it was. No, I haven’t sealed the sides. It would be interesting to see if would alter performance if I did. I haven’t had too many hiccups with the carb other than the occasional gumming up of the idle screw that I’ve had to blow out once in a while. (this is Scott, by the way). What’s your take on how a better fit on the filter might impact performance?