Sometimes you can get the same sound out of the 346 cam if you tighten the valves down to about .022". What we've found in our dyno testing research is that you lose cylinder pressure when installing a higher lift camshaft such as the 140 so there are trade offs. Bigger is not necessarily better all the time. The 140 uses a lot of fuel on the street too.
When I first got my Z back in '84 I read about the offroad cam and when I rebuilt the motor in '85 I bought the Crane Blueprint version of the "140" cam and stuck it in (well , had the machine shop stick it in)...more lift, more duration..had to be better right? With stock compression, stock exhaust manifolds and the stock intake and carb it sounded wicked at idle (everyone thought I was running headers)and at full throttle. But boy oh boy did it suck fuel (jsut like Jerry said) and off the line it couldn't get out of it's own way (didn't help that the car had 3.07:1 gearing either)...and abolutely no vacuum at idle. In '98 I changed the gearing to 3.55:1 and that made it more enjoyable to drive around. In 2003 (after years of procrastination) I decided to crossram it...and read Wayne Guinn's books. The crossram in combination with Stahl headers final made that cam wake up (Just as Guinn said...it is a package deal, it was all meant to work together)...now it runs very hard, is more enjoable to drive (except when cold) but still sucks fuel like nobody's business ;-)