Your weak link is the block strength. Study up on that! Every bit of weight you can remove from the rotating assembly will help.if it were my build, i would start by grinding the crank rod journals to 2.1 smallblock chev. Order BME aluminum custom rods in the longest length that would work with an 8,000 rpm effort. (6.760?) Then a custom piston built as light as possible, with the thinnest rings recommended. Obviously this is a hi dollar recomendation, and only if you trully want to go as fast as possible at 388 cubes. With the right cam, heads and intake (tunnel ram?) you will need AT LEAST a 6500 stall comverter, maybe more. Maybe 7,000? Builds like this are not for the faint of heart. EVERYTHING has to be right, or you risk much! But the sound of that combo will be impressive! If all possible is done to make it fly, mid tens are possible. Maybe quicker, depending on conditions.