\"Double Pumper vs. Standard\"

Will simply swithing from a Holley 4160 4v to a Holley 4150DP
increase power?

All else being equal - no. Fuel is fuel, the engine doesn't know what carb is sitting on the intake. When the calibration is optimized, in a drag race application, the DP can enhance the power curve - but may still not make more power. My 650DP and 750 VS make the same power, the 650DP is quicker. My 750DP is slower, hurts both power and torque.
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both are 600 cfm, I was given the DP recently and was just
wondering what, if any benefits it would have over the VS
I've been running for years?

Back when I had a 351w in my little ranger I first started out with an old 600 dp... I tuned it till it ran its best. I let a friend use the carb for one thing or another and one of the mounting taps broke off. I put the carb to the side and hunted down a old 600 or 650 vs holley. I totally rebuilt it and tuned it till it ran its best. The truck ran better with the vs... probly because the ext cab ranger was pretty heavy and the dp would put too much fuel in at first even with the small squarters. The dp never had a hesatation and it was smooth but for some reason the VS did run better all through the power curve. Little ranger ran in the 8's at the 1/8 mile
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I also heard that if your car is a manual trans. dp's work better, which my car is a 4sp. Any truth to this?

Yes thats true if the application is on a stock engine and trans.Often a stock automatic has too low of a stall speed for all the fuel when you stomp the pedal on a DP.With the manual trans you can rev it up a little.I have had the same experience as Ckelly.My 750 VS and my 650 Dp will both run the same speed in the quarter but my Dp is quicker.Most VS carbs have way too stiff of a spring controlling the secondaries,especially on a small block.If you buy a spring kit and look at the applications the stock spring in most carbs is set up for a 350 CI engine at very high rpms before the secondaries will open properly.This is usually why a Dp carb may be quicker if the VS carb is not properly tuned.
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dp carbs need rear gear &/or higher stall converters to work properly. we used to figure a minimum of 4.10 gears with at least 2500 stall or better. with stock gears & converter it will bog when you pour all that gas in at once.
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That totally depends on the engine vs carb size.On a small engine you can cover the bog very well by using a heavy pump shot.
But the intake charge velocity will fall so much that a slightly,rpm sensing,vac sec carb will make the car quicker.

On the other hand,i had a home tuned dp 650 on my 10.5:1 460ci.
That combo had a monstrous low end even with the 3.00 gears.
There was just always enough vacuum for that carb...

When i switched to a tuned 800dp (flows more) you could really feel the need for the 3.9 gears i'm running now.

..hope that helps..
old school olli

The DP has the capability of being faster, as long as the person running the go-pedal knows how much throttle the engine can handle at a given RPM. The VS takes the brain work out of it, but the secondaries aren't able to open as quickly as with a DP, so on a stick where you let off the throttle to shift and then get back in the throttle, the secondaries can take some time to open back up after the shift. On an automatic, where you just hold your foot to the floor, the slower opening secondaries aren't going to affect your ET much.
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