Are their insurmountable problems with replacing my Deuce TC88 with
a factory new 120 that is not specific to my 2005 Deuce?

 

Will not fit. The 120r is for 07 up Touring and Softails and 06 up Dynas. Different primaries, compensators, etc. The 120r fits 6 speed bikes.

Might fit if you also change inner and out primaries, clutch, transmission, compensator, primary chain, starter, etc. 2005... may have to change voltage regulator and stator too. Then... with all of that, I'm not sure if the wheel would line up with the output pulley from the transmission.....

 

In other words, build what I got or are there other engine options available?

 

Lotsa engine available!!!!!

S&S has engines. R&R has engines. YOU could buy and install a G2 and smoke em all!

In reality... the 120R is about the ONLY engine for 6 speed bikes where the 5 speed bikes have a bunch of choices... but they DO cost more, tho.

Having a Softy will limit things a bit ("B" engine)... but S&S has you covered.

Look at THESE powerful engines and you will drool all over yourself!!!

http://www.starracing.com/vengines.php

 

S&S is our choice here, and makes most others look like there running in reverse.
From a 107" to the formidable 124"s.
And yes, those can be modified yet, in particularly via cylinder head work, to establish great reliable gains.
Scott