What transmission are you going to run behind the 350? The answer to that question may alter the answer to how to drop that sbc in.
There are plenty of posts that deal with dropping a sbc into an ad truck. The most notable problem is the clearance issues with the exhaust and the steering box.
Are you trying to run the 350 with the stock type of suspension? Mustang II? Camaro clip? Again the answer to this question might alter the answer to your original question.
