Originally Posted by mcollinstn

You want to carb it for max power? Any wide-open vacuum more than 1.3" is hurting your max output.
If I'm looking for all out max for a combination, I don't want to see more than 1.0" of vacuum.

But, if you carb it for less than 1" of vacuum, it will not behave as well when nursing the sticks in rough water since the signal thru the venturies is weaker at real low vacuum. You can make up for it with the accel pump cam, but then you end up squirting the heck out of fuel in there. If you commonly run wide open in rough water where you have to be constantly on the sticks, then stay above 1.5" of vacuum wide open.

Tapping for a vacuum gauge? if your intake doesn't have a tap, most carbs either have a port on the baseplate OR many are spotdrilled in the correct location for you to install one there.

Having a vacuum gauge hooked up also helps you get your idle mix and static timing figured out. Sometimes hotrod boat motors end up with way too little initial timing, and too much centrifugal advance with soft springs that end up with "hunting" off idle around the docks. It's not just a supercharged thing.

Intake manifold restrictions will not show up on a vacuum gauge. The gauge is on the wrong side of the manifold to mean anything if you suspect your intake of being a problem.

M

Originally Posted by ezstriper

I think you should be close, tuning with a wide band a big plus...you can be shocked sometimes, also the newer carbs, I like quick fuels, are very adjustable thru out the RPM range, another note the prostock engines do pull vacuum at wot for max HP so not sure where the figures come up with runners/carb being to small...theirs sure are not...

Originally Posted by MILD THUNDER

You sure your throttle was opened all the way?

Originally Posted by SB

How was the exhaust set up in your shop. Meaning, where the mufflers connected directly to the header collectors or how long of pipe before mufflers ? Was pipe same diameter as collectors ?

Without heavy thought, sounds like an exhaust wave tuning issue where the mufflers had you at a better length.

Originally Posted by Mr Maine

So one side is running mid 12s and the other mid 13s. Because of this I didn't push it too hard into the 4 barrell. Need jets but not sure why the difference. Can float level do this? Motors are both strong and I never would notice this difference without the gauge.