In former life we used an air compressor to pump up the cylinder for a leak down test (how long it will hold air) through the spark plug hole as well as hold the valves up to replace the seals. But there was a rocker arm stud to anchor the valve spring compressor - may not be anything on the savage head to do this and after you've pulled off the head cover it's doesn't look like it's much more work to pull the head as well.

The early airbox can't be all that different. I checked my catalogs at work, from cheapo to expensive, they ALL list the filters fitting every Savage.  ???  I might have a early airbox in the parts bin...I ride a 98... if I find the old airbox, I'll do a side by side and try the current replacement in both airboxes. No promises, the used parts area is under "re-organization", the airboxes are somewhat AWOL at the moment...  
-WD