Just an fyi, yes as CRT said you have to pull the trans to change the int lever, but there is much more than going to a 5.0 lever, and in fact unless you mod the number of drum srings etc, in most cases a 4.2 will yeild a better shift. it is all about timing.
I also would install a HD int strut band apply to if you go to all that trouble.
You can get into trick front pumps, drums like the Hemi and 6 pack cars and motor homes that used the 5.0 also had more clutches and plates and HD 4 planetarys as well.
When you get real trick you can even drive the drum to all the fluid to escape faster and allow dfor the clutches to engage even faster.
I hhave been building TFs since I was 15 and I am 50.
My Dart has almost as much $$$$ in the 727 as a 416 stroker about 7k. You can get real crazy on hard parts etc. it all depends what you need and want.
But CRT makes some great points and I would at least go with HD strut applies and billet servo apply pistons.
In a MVB trans the pressures are MUCH greater and these parts will greatly improve performance.
And if you have a 4.2 lever you are OK, but a 5 is great if you make the needed mods, it is all about matching and shift timing.
It is not just about how hard the shifts are but the quickness of the shift and removing as much overlap as you can..
good luck and enjoy:)
