Given enough time and money, you can do anything with anything
(pigs can be made to fly given sufficient thrust).

An average V8 motor is going to be far to wide and lots too
heavy for the stock engine bay of a 140. It was designed to
take an inline 4 (or inline 6 with the 164) and with a V8 you
will have to hammer fenders, cut the firewall, and you may have
to remove the motor to change spark plugs.

There are aluminum narrow V V8 motors -- the buick / rover
V8 leaps to mind. This is the most common swap for small british
cars getting V8 motors. I'm pretty sure they don't even weigh
a whole lot more than a B20, either. Of course, they aren't
wonderful motors and there isn't a lot of go-fast stuff for
them. On a cost per speed basis, a hotted up B20 / B23 with a
supercharger (b20) or turbo (B21/23) will likely get you into
or past the buick V8 power range and weigh less.

If you've got some crazy aluminum chevy 350 that you want to
pack into a little old lady's old 145, I'd say go for it but
you're in for a pile of work. A very large pile of work.

I'd say for the money you're better off buying a "needs help"
iso grifo.
chris

If you really wanna know what it'd be like, get out your tape measure
and figure out exactly where the V8 would be. The engine room is fairly
spacious for an inline engine but not for a v-type. I think it would be
a lot better fit in a 240.
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma

I have some photo's of a full noise 142 racing in the 70's with a chev 5 litre motor, its a pretty tight fit, I may post some photo's if I can figure out how to do it. I seem to remember some street 140's with V8's but they all require major surgery due to lack of width.
Hans