Sounds like he's going to weld a B/RB bellhousing onto a 518
You may consider using a A618/47RH. It can handle more power than the A518. I would assume you could weld on the ultrabell since it to is aluminum(along with the bolts). I believe the pump bolt pattern is the same between the 518 and 47 so the ultrabell would be an easier install. I see they make a adapter plate to install a ZF8 to a big block, That would be even better than any 518/47rh but would need a controller to run it.
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