$20 and you can have mine, it's the one from the first link and has only 6 tanks on it. If you research this engine you will find it has a very bad rep, they make very little power and are hard to tune, they also leak a lot due to the poor machining. That aside, the exhaust system is a bolt on so for it to fit in a savage the end of the header will be up around the top of the head instead of down low like normal. The one I have has the bigger engine mounts cast right into the block, the black one isn't as bad but you may need to grind them off to get it in the engine mount. Quality wise, I would put it next to the $50 toki .28's the 4.6 you have now will run circles around it all day long.
As for your tuning issues, it's winter. Getting a solid tune can be a crap shoot due to the massive temp changes the engine goes through. It is pretty hard on these engines to run in the sub zero temps as they need heat to run and tune properly, hit a snow drift and it will suck the heat right out, then it's wet and will continue to have the heat sucked out until it's dry. Now the engine is freezing and all the parts are contracted so "break-in" for lack of a better term starts to happen at these cold temps. Once the warm weather hits and the engine is able to maintain a "normal" running temp, as the parts expand, they become more loose fitting which means the engine is usually worn out. I may have a SH .28 three port you could have for $60, it may need a new head button but they are universal and can be found dirt cheap, it's just past break-in.
