For V12 Conversion i offer engine mounts to build in the V12 Engine from BMW 750i and 850i in E30. The Mounts Typ 7 fits with M70 5.0, S70 5.6 and M73 5.4 engines.
A E30 V12 rebuild description you can find on my www.e30.de website:
M3 E30 Replica project with M73 engine