The Enya 29 model 5224 was first made in 1964 and yours is the more common plain bearing type. No other carb can be fitted to yours because of the square intake housing and the water jacket is a shrink fit over cut down cylinder fins.

The 45 model 6001 was an absolutely incredible CL stunt engine back in its day (early 70's from memory when I bought mine). The Enya 60 is a 60-II from 1965 and has two rings like the 45.