The Savage is a low compression engine and shouldn't need a high octane gas,.. so maybe the Lucas cleared it up.
High speed wobble is not a problem with this bike, but it is a light bike and the front end will get lighter at speed, so you may just be feeling normal road surface wiggle amplified by speed.  If you have a windshield it can lighten the front even more...
If it's an old bike, jack up the front and wiggle the fork side to side to check the steering stem bearings... and you're already checking the tires,... if you get the front off the ground, you can basically check the tire balance yourself by spinning the wheel and seeing where it comes to rest,... if it always stops at the same place, it's out of balance.. bad tire balance will usually cause more of a pogo feeling than a wobble..

If the front end checks out ok, get the fork brace. I put one on this spring, and the diference is night & day. It really smooths out the front end jiggles at hi-way speed. Also,  any effects from small ruts etc. in the pavement tend to be minimized.  Aboutely, money well spent.

if your tire is reasonably balanced, your pressures are ok, you lift the front and dont feel any slack in the neck, it leaves only a couple things... swingarm bushings(unlikely, causes more of a "crabwalk"),or a problem noted on panhead and earlier harleys... neck bearings too tight....just like a car's wheelbearings, a steering neck needs just a tiny bit of slack.... if you can feel it, it's too much...according to clymer, initial torque to 29-36 ft lbs, turn neck lock to lock 5 or 6 times, then back stem nut off 1/4 to 1/2 turn... have you checked your spokes? if none of this shows anything wrong, then pull and measure fork springs... a bud with a virago got a vicious 90 mph deathwobble from one being 1/4 inch shorter than the other....
edit: just checked the front-end section of the clymer....could also be the springseat for the top spacer being assembled in the wrong spot, or missing.... check how they're stacked if you get to measuring the springs... proper order is spring, seat, spacer(also make sure both springs are right side up)..... of course, not having the right oil, the right quantity, or an imbalance of quantity between both fork legs could cause it.... changed your fork oil lately?

  Matt I made one of the lifts really neat,And fast getting the bike up

Is this a new thing for your bike or is it the first time you had it to speed????  

If it only happens at a certain speed and it can be repeated, then I would tend to lean towards wheel/tire balance.    How new is the tire??

The frame/front end geometry is stable. But the forks are a bit spongy & needs the brace. You have as classy a tire on as possible. If there are "No Wobble" times, then its not balance or a bad tire. Id point to road/fork rebound & flex & go for a fork brace. Even IF that doesnt solve the problem, you need one anyway & chances are its gonna be the answer.

Wobble like tank slap may be another issue than what we're used to.

Something's out of balence or not straight.  Sometime the fork's can get tweeked, sight along both to see if they're parrallel to each other.

Loosen the cap and lower tree pinch bolt and spin the tube to see it it wobbles.

And I'd check the fluid.  When I changed mine, the fluid was up near the top of the tube when you let it drop into the bottom slider.