Alright. First, I feel it is important for you to take note of all the parts/tools this job will require as well as what labor you will require (either from your or someone doing the work). Things you will require to make a starter 110 is new cylinders (can't bore stock that far), piston kit, cams to allow more air in (if you don't at least cam up you are wasting your time), valve springs depending on the lift of said cams, intake, clutch spring. Things I would suggest you also do to actually start making use of that displacement are a new intake, new throttle body, port and polish your heads, choose a proper compression for your cams while you get the heads done, I would go with a full exhaust system instead of slip-ons (supertrapp 2into1 if you are trying to build good power), I would consider the Screaming Eagle compensator upgrade (the stock ones in 96 primaries have caused some starting issues depending on where you are at, only fix we saw was upgrading to SE. The problem was amplified of course with performance parts), compression releases with your head work. I don't know if I am forgetting anything. I prefer the Super Tuner over the Power commander, but that is preference.
Alright....The work that is required. You have to fully remove your engine. Then you have to fully disassemble the engine all the way to cranks. Find a VERY reputable machine shop that deals with harley work and have them bore you cases to fit the 110 cylinders. Going to a 110 is more than a 103 if you didn't know. The cylinder spigots of the 110 will not fit in the cases without machining. Once you get back the cases, THOROUGHLY clean the cases to verify no material is still in the cases from the machining process and replace all bearings. Then fully reassemble the motorcycle with all the new components. Would I say it is a beginner's task... : /. I don't want to discourage one from having fun working on their bike, but it is a pretty decent size job even for a common mechanic. You will require all specialty tools necessary to remove and disassemble the engine which add to the cost of the build (though now you have to tools for later work...so i see that as investing).
If that doesn't deter you...and in fact sounds like a fun task that you are up to then have at it. I would also consider a 103 kit. A 103 is a proven build you can get very good numbers from and doesn't require machining the cases. You will require many of the same parts, but not as much labor or specialty tools. You can also save a few bucks by having your current cylinders bored to fit your pistons. With the money you save from not having to do the machining, buying extra gaskets, buying all the specialty tools right now....you can better afford other upgrades (head porting, etc.)
120r option. Well...just don't look at the base price of the 120r....because there are other things you pretty much have to get once you get that engine. Like you will require a new exhaust and intake. You will have to get a new clutch. That is a lot of power. It needs a lot of air in and out. It also needs the rest of the powertrain to be beefed up. So...yes the engine is a bit over 5k....but by the time you get it on the road it is going to run you like 7k-8k if you are thrifty. If you go with that serious of an engine, you shouldn't go in half-arsed or it will kick you in the teeth. Again, not a deterrence...just fair warning. I would love to do that myself....but I don't have the wallet to do it right. You would have to go through and price all the parts and cost of the machine work to see the value of the 110 vs the 120r. You could also factor in the possibility of selling your stock 96, but you would need to be reasonable in factoring that unless you already had a buyer.
Personally I would do a 103 some cams and heads for now. Of course I don't know what budget you are working with. Also I don't know your level of knowledge or the real bottom line for how much power you want. Reliability is another major factor. Can you do it? Sure, I have seen it done on the same exact year/model bike...and the guy had a sidecar put on. Its just not going to be a weekend oil change or a set of slip-ons. You forget a bolt on slip ons....they fall off and you lose $400 for a new set. Forget something in the engine or don't torque something properly....say goodbye to a few thousand. Have fun with whatever you do.
Steel
