This is relevant to my interest, so I'm trying to put it in context. When I compare to the Toyota part #s 14309K and 14309L, they are splined on the inner end while yours is on the outer end. Could you show the parts against each other and/or the case?
Could your machinist produce two of the six-holed part with 4 holes on a 3" circle? Because that's what I'm thinking I need.
Also, this is old news, but I'm not proud of it. I just need to clear the table for the new year:
I got the subframe, just so I could see it. I thought I might be able to cut the middle 2/4ths out of it and use that. Alternatively, I wanted to know if it could carry a front-wheel drive suspension and steering. I conclude that might work in a rear-wheel drive configuration, like in a kit car.
I've decided to go back to Plan A, a bracket welded onto the stock transmission mounts. I've had a piece of C-channel that would work, but it weighs as much as half this subframe.