I have found out these Enya parts can be used for these other engines.
Enya 45 6002 Head will fit perfectly the ST G21 46
Enya 60 III Head will fit perfectly the ST .60
perhaps other parts will also match, but I havent check it out.
Enya muffler M251 will fit OS 35/40FP 40/46LA and Fox 35. It is much lighter and smaller muffler then the OS and FOX ones.
Enya 19 muffler steel bracelet will fit FOX 35 40th A. if you'd broken muffler ears
These parts can be purchased from Randy Smith.
Martin