340s arent worth any more then a 360 when throw a rod out the block on the strip. I sold my old 340 for $900 you could probably buy 2 or 3 running 360 for that price.
Id find a nice 360 add a set of magnum heads, RPM intake and a comp cams 280H. With a set of 3.91s and a 10" converter it would go pretty good and shouldnt cost much to put together. Especailly if you get the magnum heads for free and trade your 4.56 gears for someone elses 391s. Hint hint. :thumblef: