Gearbox to bellhousing adaptor thickness

[waterbucket]

Can anyone tell me the minimum thickness for an adaptor plate between a T5 gearbox and the aluminium bellhousing. I will use steel for the plate for this, I was thinking 3/8"
Philip

[BlownMGB-V8]

3/8" is the thinnest I've seen. And about 1/8" at the engine.

Jim

[ex-tyke]

A couple of things......Make sure that adapter plate thickness chosen doesn't compromise engagement of the pilot bearing/xsmn input shaft....
......and ideally, plate thickness should be  1-1/2 times the bolt diameter (otherwise ideal fastener torque is not obtained)....if 3/8" steel is chosen, I'd use NF fasteners/threads to allow a higher fastener torque than NC fasteners.