Carbs all do the same job, though not necessarily in the exactly the same
way. Sometimes, the stock carb is restrictive so a larger choke diameter
will allow the engine to breather better at higher revs. However, there is a
great danger of overdoing this, so the gas speed is reduced to the extent
that the fuel doesn't atomise properly.
Engine tuning is essentially about getting a bigger bang to happen faster,
which is why much of the work involves allowing mixture to get in, though
and out of the motor as quickly as possible. This is why cam profiles and
exhaust/inlet flow get so much attention.
The other element of tuning is accuracy-i.e. balancing combustion chambers,
tweaking advance curves, etc. so as to make the events in the engine happen
in under tighter control. In this respect, a Weber is, arguably, a better
unit than a Zenith, in that its provision of the right mixture for different
conditions is more accurate.
Remember, though, a Weber on its own won't make a huge difference and the
additional mods depend on numerous factors, including choke diameter.
Hope this helps,
----- Original Message -----
From: Tab Julius <email@example.com>
Sent: Saturday, August 05, 2000 8:23 AM
Subject: What are the true benefits of a Weber carb?
> Today, a gorgeous day, I met two (count 'em: 2!) MGs driving in my town, a
> small town of 3000 people where I probably have the only one, unless
> someone else is keeping theirs tucked away.
> One was a B, the other a Midget. I talked to guy with the Midget, who was
> just passing through, and he told me how he had reconditioned his,
> including replacing the Zenith with a Weber. He said it was a definitely
> noticeable major difference, although he didn't elaborate (and by then we
> were out of time). I have a '78 B, and now I'm wondering, if I moved to a
> 1) What significant differences would I see?
> 2) What would be involved? Is it just changing the carb, or do I have to
> do the muffler too, or what?
> 3) For those of you who moved from a Zenith to a Weber, what did you
> think? How much did it cost, and would you do it again?
> - Tab