Th400 Or 700r4

[eightbanger]

Took my truck on it's first long journey the other day 4 hr round trip most of it on the freeway and she took it in her stride It's running a 454 mated to a TH400 which has been tweaked by the po (see sig) and all the while I was wishing I had a 4th gear...cause driving at a steady 75mph the engine was really reving high, had the radio up real loud just to hear it there was a lot more to go on the gas pedal but if I took it passed 80 mph they would have heard it in Scotland. My question is this, would swaping out the 3 speed auto TH400 for that 700R4 that everyone seems to be going for solve this? is my engine reving that high at speeds cause it needs a 4th gear. Then i'm thinking is there a down side to having a 4 speed? like losing the power that I have now just running around at lower speeds. Or is there a better trany out there that would give me the best of both worlds? any help or sugestions are appreciated.