if you decide to go a big block,just keep that nice 289w package all aside and dont chux anything out as stuff is getting hard to find and very pricey,those 289w scream their head off when throwing some coin at them,and light too,if it was me i would keep the block ,buy a 347 stroker kit,some afr or other alloy heads,nice carby and manifold,and rebuild the c4 you already have with a street stall converter and off ya go.