Depends on the 4 barrel. The quadrajet has smaller primaries than
secondaries. The holleys have 4 equal sized. The secondaries on the quadra
jet are vacuum actuated so they open as the engine demands. That will be
under higher loads but that is not some specific throttle position.
Obviously it tends to be the more open throttle positions. The holley can
be had as a vacuum or mechanical secondaries. The main reason for a bigger
carb is to deliver more air/gas at wide open throttle. The holley typically
is not the best choice for fuel economy but is preferred for perfomance.
The holley is also so common that they are easy to find parts for.

wrote in message
oups.com...
I do agree, that you probably wouldn't ahve that much ore to gain, but
I suppose it depends on what you want. For pulling a ski , i would
think you could get a better hole shot, and plane out quicker. But I do
agree,t hat you probably wouldn't notice that much difference on top
end.



But even so, arn't the fron two bbls. usually smaller on a 4, and the
bigger back two usually kick in at 3/4 to WOT?


Lee henning wrote:
The other three things that may contribute to higher horsepower are the
cam,
compression ratio and valve size. You should check out those things
before
you go to the trouble changing the carb.
LD
"crystalguy" wrote in message
oups.com...
I recently purchased a 1988 Sea Ray with a Mercruiser V-6 4.3 with a 2
barrel carb (175 hp)
Is it possible to convert this to a 4.3 with 4 barrel carb (205hp)
Is it just a matter of changing the carb and intake or are the
ingnitions different?

Any input would be greatly appreciated.