Worth the effort?

Basis of the question is after getting a 2nd and 3rd opinion my year old 3000rpm advertised.recomended convertor will only flash around 2500rpm and is the cause of my gutless off the line performance.

Now the 727 in the car is in good shape iternally BUT many of the holes in the case are helicoiled and it has developed a few leaks the last 2 years.

Now the driveshaft is a Bubba special that was cut down frm a Fury and needs to be retubed and balanced anyways.

So the question is: Is it worth the while to swap a 904 in place behind a moderate built 340 for street use? Its a full weight stock car with 3.55 Gears. Thinking the lower first gear might be nice on the street.