Bringing a C-15 back to life

[Sothpaw]

i recently purchased my first sailboat and have a ton of work to do to bring it back to life. it hasn't been in the water in 10 years. i got the wrong mast with it and i need to do a few minor fibre glass repairs. i have the racing sails but the mast is 4.5 feet to short... it seems that 3 owners ago they knew about this problem and tossed in a spare mast from some other boat with a slightly larger diameter. if i have a metal shop mill me an insert that would fit the two peices together by putting the extra mast on the lower 4.5 feet.... would that structurally work... i braced some 2x4's on the lower 4.5 feet and it seems to actually hold so i think i'm going to try it out... the price of a whole new mast is crazy and i think i can actually jerry rig it. anyone ever done anything like this?