I'd suggest you go to a salvage yard and have a look at a
240 and a 140 side by side.

You'll notice that the 140 has a motor that sits straight
up and down, has the intake and exhaust on the same side,
a steering system with an idler arm and steering box, 2
wishbones, 2 ball joints, etc. The 240 has a motor that
sits at a slant, the intake and exhaust are on different
sides, and the steering uses a rack and pinion thingy.
I'm sure that there are other differences in the front
suspension but I've never checked.

In other words -- I hope you know that you can't drop
a warmed up 240 motor into a 140 (unless it is a 1975
240) without significant reengineering. Also, you can't
use a 240 transmission on a 140 because one motor sits
at a slant and the other doesn't so the shifter would
be sticking out of the tunnel at an angle and poking
someone in the leg. Unless you have a super rare
bell housing...

The bars on 140s are the same between all years and
all of them have only fronts. IPD sells a kit with
fatter front and new rear bars and it is well worth the
cost.
chris