OK, but aside from opening up the restrictions between the filter and the pump, why do you want to? The 427 top oiler was a fine design and enless you are going to turn it into a cammer it really isn't worth the trouble (expense)..
Before you flame me.. What are you going to gain? Will it be more valuable? NO (actually you will ruin a perfectly fine 427's historical value).. Will it be more durable? Not really..
The side oiler was developed for the SOHC 427 and was plumbed for oiling accordingly. Beyond that what will doing what you propose gain?
If you must embark on a project like this I would (ok.. I wouldn't) use a 427 industrial or marine engine.. These are the ones that "look" like side oilers with the raised
oil passage on the side of the block.. They were cast but never built as a side oiler.
You can find these engines for well under 2k-3k for a core and they have no historical value. 427 top oilers are too few likely expensive to chance this on..
Better yet.. Go with a Genesis iron 427 repo.. I think those are in production now and would be better and cheaper in either case.