manifold ref'd carbs

[Blown 472]

Would one ref both power valves or just the primary side??

[78Eliminator]

There you go again, asking about boost referencing...

[paradigm shift]

If you do not reference both I would plug the secondary side and jet it up. I run a 29' boat and at cruise RPM 3500 to 4000 I run like 0 manifold pressure and around 12" of vacuum under carbs. I want that power valve open at that time. I have plugged the secondary side and jetted acordingly. I very rarily get in to the secondary's unless it is WOT!! :D It is really a preferance and you will probably get many opinions. Either way will work just do not run it LEAN. eek!

[Blown 472]

78Eliminator:
There you go again, asking about boost referencing... I got some good info from holley on two diff ways to get tha vaccum to the valve, just wondering bout them secondaires.

[Hotcrusader76]

Blown472,
On most systems the primary is all you need, since that's where the low to mid RPMs run at for moving around in the water.
Some street car set-ups benefit from both being referenced, but that's on a rare occasion.
Note- there are two locations that can be utilized for plumbing the vacuum source in to the carburetor. One being the baseplate and the easier of the two using the old ported vacuum connection on the metering block. Both are reliable and secure from vacuum leaks.
Good luck.
~Ty

[RumRunner]

You would boost reference any place you're using a power valve. If you only ran a pv in the front you'd boost ref. the priamary side, if you run a pv in the secondary you'd boost ref both sides.

[schiada96]

Holley does both sides on their blower carbs