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Which jets

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Old Sep 24, 2009 | 07:11 PM
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Default Which jets

I replaced my 670 street avenger with a 650 double pumper with mechanical secondaries. I dynoed the car with the 670, the jets were 68 & 70. Should I have the same with the 650?
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Old Sep 24, 2009 | 08:24 PM
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Originally Posted by painterman52
I replaced my 670 street avenger with a 650 double pumper with mechanical secondaries. I dynoed the car with the 670, the jets were 68 & 70. Should I have the same with the 650?
no..they are metered differently, surprisingly you may want to richen the dp or at least give it a try...on the other hand, the street avengers are jetted too lean out if the box....good luck
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Old Sep 25, 2009 | 09:20 AM
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no,
what model 650?
does it have 2 power valves?
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Old Sep 25, 2009 | 04:12 PM
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#4777. Yes it has 2 power valves. They are 6.5. I have about 13 inches of vacuum at idle. I have performer rpm heads and a lunati flat tappet cam 227/233 @ .50 110 lsa.
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Old Sep 25, 2009 | 04:26 PM
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71 & 76 is what my book says, stock.
that is race carb that series is infamous for running rich out of the box. All 5 circuits will need tuning for proper street use.
Good for the drags & dyno if that is your hobby.
what intake do u have?

Last edited by Matt Gruber; Sep 25, 2009 at 04:49 PM.
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Old Sep 25, 2009 | 05:29 PM
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Performer rpm intake. there are a number of different models for the 4777 I think. I have 67/73 jets. I`m not positive about 2 power valves.
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Old Sep 25, 2009 | 05:55 PM
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if u r happy with the way it runs, no black smoke, go get a dyno test.
.
if u or anybody else with a gas sucking drag car want to convert it to a 17-19 mpg cruiser with NO LOSS OF POWER at the track, there are several ways to do that with a double pumper made for the street.
My favorite combo for u:
4165 holley DP 650cfm
performer RPM Q-jet #7104
base gasket 108-21

Last edited by Matt Gruber; Sep 26, 2009 at 12:36 PM.
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