Welcome aboard!
Secondly, I agree with Steve, if you want simple, stay in the same engine family. If you want LARGE, there is always the 460. You should be able to pick up some parts/mounts/stands from a 460 equipt truck of the same era and use them to transplant in BIG cubes. Another option if you go that route is check out ebay or L&L, they supply similar swap stuff
--Mike