This may be a crazy idea, but does anybody know if it is possible to take the innards out of a 5 speed and put them into the case of a 4 speed to upgrade the tranny on an older Savage???

I was just thinking out loud.  I've never seen the inside of either case and don't know how different they are.  Looks pretty much the same on the outside and so little has changed on these bikes in the last 22 years, I thought maybe it might work.  Never know unless you ask, right?

4th-5th isnt much of a jump anyway. I wouldnt sweat it.

It may not be impossible.  I know as an example that you can bolt in the 6-speed box from a W-series GSX-R750 into a W-series GSXR1100 motor to replace the 11's 5-speed box, so this sort of thing can sometimes be done.  The 6 speed box has slimmer gears (but is still strong enough) - there's only so much space in there.

Looking at the small difference between top gear ratios for the 4 and 5-speed Savage, and given the nature of the motor delivering low end / mid range rather than high power, I think in most situations a 4 speed might just be a more relaxing ride with less gear changes.

I really appreciate all the info.  I am looking ahead to winter projects; planning to rejet the carb and fix the top end oil plug leak too.  Don't think I'll explore the 5th gear option any further, expecially if it doesn't make that much of a difference in the way it rides or fuel ecomomy.

One of you guys from the service clear this up for me.  Is that what is referred to as a "blivet?"  "Can't fit three pounds of crap in a two pound bag?"  I can't remember now where I heard the term, but I have an impression of a uniform in the memory.  Maybe I'm totally off.