manifolds?????

[mr j-man]

hey!

ive been recentley been looking into getting a new intake manifol for my 308 red carb motor
and was wondering on what the differences are between single plane and dual plane maifolds
e.g edelbrock performer and torker....
what pros and cons do these manifolds have between each other????

thanks heaps

[Calaber]

I can answer part of your question. Single plane means that the carb feeds into one single level chamber (called a plenum), from which runners to each cylinder carry the fuel/air mixture. A dual plane manifold has a two-level plenum, with the upper level feeding one side of the engine and the lower plenum feeding the other side. It is easy to tell the two designs apart if you look at them side by side. The single plane manifold will have one big hole below the carb mounting, with runners feeding off to each side of the manifold and a dual plane has that hole divided down the middle. You can see the upper and lower levels.

I don't know the exact reason for the difference but I suspect that one breathes better at lower revs for better low end torque (which you might need for towing, for example) while the other breathes better at higher revs for higher top speed. (But this is a guess, not a stated fact).

If my guess is correct, I don't know which design is designed for which purpose. I'm sure a few other guys with carb V8's on the forum can tell you though.

[glenn l]

calaber has the differences spot on, and im pretty sure a single plane is more used for full open throttle applications like a drag car where a dual plane works better down low to mid range. a factory manifold is dual plane.

[Brett_jjj]

Yep,the single plane will give good top end power and torque high in the rev range,whereas the duel will give better low to mid range torque and power.I used to stuff about with these years ago on 351 fords etc.

[mr j-man]

yeah thanks! i had a feeling s/plane manifolds were 4 higher rpm.......im really after a hi rise manifold!
do they come in dual plane or not.... iknow ive seen them in s/plane version but never a d/plane........
is there such thing?

thanks guys

[mr j-man]

or would it pay just to keep the 2 inch spacer between my carb and manifold?