I've heard it said that you can keep old Fox 35's going with parts from newer models, - a tribute to a continuous line since 1948.
Maybe the same applies to 29's? Or even, - it it's just a case of thick or thin cylinders, maybe a 35 p/c would really cheer your 29 up
(Guess that would also mean a different head).
I think the real answer is you'll have to check.
Let us know?