The Project Pad

I am to the point where I need to make mounts for my tdi swap. I have a bunch of 3/16 mild plate, is this thick enough? I would use 1/4 to be safe, but if would be nice to use this if possible since I have it right here.

That is completely dependent on the geometry of the part. You could make it out of sheet metal with the proper design...

ok true. Not sure how to describe what I am planning. There will be a plate at the block with 3 bolt locations and a plate that rests on the factory mount with a slotted hole. To connect the two I think I would use a flat piece of plate with a perpendicular brace of plate to support it, sort of like an I-beam. Not entirely sure what it will look like until I start mocking it up.

sort of like this construction but with steel.

also keep in mind that this will be a 250ft lb 130hp tdi, not a 500hp drag racing monster.

3/16 will be plenty, its all in the gusseting

I'm not sure what the dimensions are on that aluminum mount, but you can consider aluminum to be roughly 1/3 the strength of steel... therefore 1/3 the cross sectional area required for the same strength (generally speaking).

As Tim said, all in the gusseting.

Will be more than enough

My motor mount plates are 1/4" thick. I also designed them in mind with high horsepower / torque cars to beat on them repeatedly. 3/16 will be fine for your application