I don't like the biscuit type mounts, they worked on 40's fords because the enclosed drive line -torque tube tied the engine-trans and rear end all together. The out rigger angle iron style will work on a chevy because they have 3 bolts spaced far enough apart to spread out the leverage. I prefer the mount shown in the last picture, more compact and it HAS the safety rivet . The middle one with the safety strap just doesn't look neat enough when you can see everything. I would build new frame brackets to weld to the frame and use the ones in the last pict. All the leverage would be transferred to the frame which should be boxed from the firewall foreward at least when doing a swap.