Depends on how the flywheel adapter is implemented. The flywheel adapter on my swap, kit from 4x4labs, is aluminum. That is NOT AT ALL how I would have done it, but that was the company's choice and it appears to be holding up just fine thus far. I had it out a few thousand miles ago but it was fine then as well.

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617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap