If I was building a 518/46RH for that application I would be using all the diesel stuff in it, drums, clutches, planets and overdrive section.
Some of the diesel stuff(drums) won't fit in the case. The 500/518/46rh is still a small block trans. An ultrabell on a 47/48RH would handle it. Not sure if they changed bolt pattern on them though.
yep, 413/440 pattern and TC is larger, thus the need for adapter or bell swap they are also 2.5" longer so trans mount and DS shortening need attention
