I really haven't tried..I was happy just the way it is. Too bad you are so far away..we will do a All American GTG at some point and I have boxes of that 82cc stuff we could mix and match to see.
They ALL interchange. For real. You will get a variance in the way they deliver oil. All of three methods i believe.
I intend to build an SXL-925 with a compression release. Or maybe I'll get an XL-923 and go crazy.
By far the most interesting difference in the XL-90X series is the use of a choke lever, rather than the knob.
One less hole in the carb box. The distinguishing characteristic between the XL-903 & 4 is the 904 did not have points. All of these saws came in two displacement varieties, 77cc and 82cc, respectively.
The Homelite XL-904 is rare. The XL-903 is hen's teeth. And I finally got one! Unfortunately, it's had it's badge removed. But I know what it is. I should put a 923 motor and an electronic ignition chip in this stinker. Put a new muffler on it and go "Gas Monkey" on this thing. The inside is NICE!