Does anyone make a bolt on z bar bracket for a 1973 455? I found a bunch for chevy and ford @ Summit and Jegs.

 

Have not heard of one, bolt on or weld into position is a challenge-can be done but easier with motor out of the car-depends on your skill level, or $$$ spend for installation etc. I'm assuming the 455 is a donor motor. Questions: has the back on the crank shaft been drilled out for the pilot bearing to accommodate the 4-speed??? If you need more assistance, dive in and give us more details please.

 

I doubt there is enough demand for an Oldsmobile bracket to justify a company putting one into production. Others here have made their own, supported by the bellhousing bolts.