The ARP shaft is a great piece, it may need to be trimmed a little to fit correctly. I ran an ARP shaft and they are super strong, due to some misfortunes i had to replace it and went with the FMS shaft, i had to trim the bottom of the distributor a little to make it fit, but they are both great!
I will say that they Milodon piece I put in is one beefy SOB. It ain't gonna break, I am confident of that. It does have to be trimmed a smidge, though.
run the efi shafts, they have a lower shoulder on them for the longer efi distributors and will work with points or duraspark also, using a "carbed" shaft my require trimming the efi distributor when using it