I am having trouble with vibration on the engine to frame ive really straightened out this engine --(I want to keep the six in it and juice it up ).
The mounts themselves were loose at the bolts to engine, after fixing that
I thought the bracket on the passenger side, (on the frame-which seemed a little strange in itself), was split out because it was slotted open to the mount when i got another one I found out they are all that way.

My question is why? and how can i fix this so the engine doesnt vibrate out of this bracket--- or should I?[B]

I think if it was me. I would replace the engine side mounts and the
trans. mount. I've seen mounts that have failed from age, yet look ok.
If the engine had leaked oil (front crank seal, valve covers..ect) for sometime, this would cause the rubber in the mounts to break down.

Hope this helps.