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My combo is .222/.226 @ .050 hydraulic cam, home ported 351W 1.94/1.54 heads (not finished porting yet), edelbrock RPM intake, 9.5:1 compression, t-5, 3.73:1 gears in a 93 mustang. This is primarily a street car - i know that the double pumpers are worth about 10 hp over the vacuum secondary, but how is drivability? If the VS carb is more reliable, much better gas mileage, more driveable around town, it probably would be better for me. If there isn't much difference, I'll go with the DP for the power. BTW, i was going to go with a 650 cfm unit. This is my first carbed car, others were fuel injection, so any experience would be great. Thanks.
 

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.......Musthave.........I would reccommend a 650 Double Pumper for your application just like you are thinking also.......A vacume secondary carb would work well also but as long as ya have the clutch go with the double pumper...If ya need help setting one up or purchasing one just let me know.......Jesse @ BIGS

BIGS Performance Carburetors 1-715-835-3726 9-5
 

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I used 600 vacum sec. Holleys for years, the first time I bolted on a double pumper I knew I would never look back. I have used them on my street cars ever since, but they have all had manual tranny`s. I currently run a 650 speed Demon on my 302 and it is perfect, I like it.
 

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I agree with what you originally said the vacuum has a little smoother operation,maybe better gas mileage but the dp will be quicker.Depends on what you want from the car.I have both but since I put the dp on I never take it off anymore but then again its not a daily driver and with my 4.11 rear gas mileage is horrible no matter which one I use
 

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On 2002-03-21 08:35, BIGS wrote:
.......Musthave.........I would reccommend a 650 Double Pumper for your application just like you are thinking also.......A vacume secondary carb would work well also but as long as ya have the clutch go with the double pumper...If ya need help setting one up or purchasing one just let me know.......Jesse @ BIGS

BIGS Performance Carburetors 1-715-835-3726 9-5
Hey Jess, whatcha gettin' for a 650DP? I'll be in the market in about a month when the machine shop is finished w/my rebuild
 

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DP by far is the best performing carb unless you have a 302 with stock 1200RPM converter and tall gears....well, actually even then I've had great luck with 700 and 750 DPs with stock converters and 3.00 gears on stock 302s. I can tune the DPs to work though. I had a '68 Montego MX that ran 15.80s with stock engine other than the stock '69 351W heads, Torker 289 intake, 750DP, PAW 351W firing order RV cam(204/214 at .050&quot
, & Duraspark ignition. Had 3.00 open rear, tall skinny radials, stock single exhaust, stock converter, and low compression. Would spin the right rear tire exactly the same on launch at the track and ran 15.80 all day night and day. Won many trophies with that car and if it didn't win, it was runner up week after week. That is a fairly heavy car and it loved the 750DP. Much better torque off the line than with the 750 vacuum secondary and 3 MPH more with the DP of same CFM rating. It would go thru the traps in 2nd gear and that single exhaust would have that load sound of air being forced out(funny sound).
 

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I don't know were the myth about the double pumpers using more gas came from. If you are crusing around town and not laying on the throttle all of the time, it should compare to the vacuum carb. It still runs on the primaries just like a vacuum carb. It's only when you go past about half throttle that you open the secondaries. That's when the secondary accelerator pump starts squirting and the gas starts flowing. The vacuum carb does the same thing but without the squirt. So, it will take some lead in the foot to make a DP use more than a VS.
My vote is for the double pumper.
 

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FXComet.......I have 2 versions of my 650 Double pumper to choose from........My Stage 3 is a #4777 carb that we race prep/set-up for your application and cost $379 complete......The other is my Stage 5 HP with Billit base,HP metering blocks,HIGH flow contoured main body,4corner idle,ect....it sells for $599 complete.....Thanx 4 the interest........Jesse @ BIGS
 

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On 2002-03-21 20:52, BIGS wrote:
FXComet.......I have 2 versions of my 650 Double pumper to choose from........My Stage 3 is a #4777 carb that we race prep/set-up for your application and cost $379 complete......The other is my Stage 5 HP with Billit base,HP metering blocks,HIGH flow contoured main body,4corner idle,ect....it sells for $599 complete.....Thanx 4 the interest........Jesse @ BIGS
Jesse - Besides selling your own, do you still modify customer supplied carbs? If so, what models and how much?
 

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SHEP927
we sure do customers carbs also..........For something like a 650-750-850 or pretty much and Holley 4bbl its $244.60 complete parts&labor and we pay the return S/H to you.......Turn around time is 7-10 days.......Thanx alot..........Jesse
 

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On 2002-03-21 20:48, clevelandstyle wrote:
I don't know were the myth about the double pumpers using more gas came from. If you are crusing around town and not laying on the throttle all of the time, it should compare to the vacuum carb. It still runs on the primaries just like a vacuum carb. It's only when you go past about half throttle that you open the secondaries. That's when the secondary accelerator pump starts squirting and the gas starts flowing. The vacuum carb does the same thing but without the squirt. So, it will take some lead in the foot to make a DP use more than a VS.
My vote is for the double pumper.
Actually the 4700 series Holley dps were designed for race or performance use so they come with bigger jets and richer idle circuits.You can't simply rejet them to match a vacuum carbs jetting because the dps have power valve channel restrictions in order to work with the larger jets.So to make them the same requires internal modifications.I'm quoting most of this from a Holley carb book as I don't claim to be an expert myself but you can see how the dps would be a little harder on fuel wether or not your using the secondaries.Does that change my opinion on using the dp.HELL NO I'd use it anyway
 

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Bigs, How much to completely replate my 9375 Dominator the stock color, re-anodize my carb linkage, and drill the power valve channels thru in the primary metering block so I have a functioning powervalve? My Dominator kinda looks ugly but runs great. I've had it for many years and it's looking its age indeed. I want it to look as new and have a power valve for cleaner street cruising(be able to lean jets since power valve will add enrichment fuel). Thanks

frdnut is right about smaller power valve channels and larger jets in the DP. The jets provide a more precise metering for racing applications compared to the power valve channels so to keep the intermediate/part throttle cleaner on the DP the channels are smaller but not gone otherwise at part throttle the engine would try to load up so the power valve and smaller channels were necessary in the DP. The vacuum secondary holleys have a leaner main circuit/jets in the fron with larger power valve channels to compensate which gives better milage but the secondary metering plate or jets are richer to help cover the hole in fuel delivery when the secondaries open with no enrichment shot from a secondary squirter.
 

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89 Coupe.......we can take care of that Dom carb for ya......Our rebuilding/recoloring cost is $266.20 complete parts & labor.......I can take care of that Primary metering block power valve issue at the same time for no extra charge.........
One thing to think about as an option is we have a new linkage design out for the Doms that does away with the stuff up in the bottom and has the connecting link on the side of the carb like a 4150 model double pumper.......It has 4 adjustable settings from lots of primarys to 1:1.......Its a $95 option and is really tits lookin.......
Thanx alot, your friends @ BIGS.....Jesse
 

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Okay Bigs...How about this one...Ive got a '71 Torino, 351c 4v, Comps XE268, C4,A/c, P/S, 3.55 no slip, and is a daily driver. Very little track, but love to throw dust on my chebbie lovers. What is your suggestion on a carb?
Many thanks!
 

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Hey De5775.....take a look at E-bay item #1815188192.........Its my Stage 5 750 Double Pumper and that is what I would reccommend for your application....This carb will flow over 800CFM on your heads and be very streetable! I can build ya that carb in many different color combos.......Thanx alot, Jesse @ BIGS
 

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ok I have a holley 735 cj carb new and a750 dp. to go on a 302 with 351w heads ported and 194-160 vales, 2000 stall 4.66 gears witch carb will be better for the wife's car
doesn't se the street much at the track most of the summer
 

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Radracing.........thats a tossup.........I would probably opt for the 735vac for the car......strictly because I dont feel you have enough stall converter to hanle the 750 DP.......It might give a bog off the line........If ya would step the converter up to maybe 2500-3000 that would open the door for the 750........With your current combo it would probably be best to have a well prepared 650 Double Pumper.....Thanx alot, Jesse
 
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