Don't know how much "budget" you have, but a conveter will be $600-$700, alum heads wil be $1200-$1600, cam & lifters $300-$400, ect.
What head gaskets are on the engine? If they are the felpro 1009 or similar (which measure approx .040" thick), put on a set of steel shim gaskets (approx .017" thick). The cost is about $50-$60 (head, header and intake gaskets) and a days work. 4.88 gears will make it just about unstreetable.
Cam timing could be usefull and cheap. Advance that cam about 4-5 degrees from recomended to get that boat moving. When at the strip, consider race fuel, then jet the carb up a size or two.
With that low compression and small cam, 40-42+ total ignition timing is not a bad thing as long as you run good fuel (110 octane).
All these things will add up and are cheap. The fuel and ignition timing can be adjusted back to sreet use.
Good luck, you can get there.

Brian