issues running double pumper?

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Mar 26, 2013 | 09:06 PM

#16

fordman75

Lead Driver

Joined: Dec 2000

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From: South central, Minnesota

Quote:

Originally Posted by 68cabby

I wish there were smaller mech secondary carbs. I say this..cuz of contemplation. I know the bigger carb I run..ill have less low end. Wish someone had a 500 cfm mechanical secondary haha. Just feel like is be losing bottomed end with a 600..at least what I've been told.

There is a smaller mechanical secondary square bore carb. It's a Holley 9776, 450 cfm mechanical secondary ( not a double pumper ) . But it doesn't have a choke. It's designed for tunnel ram set ups. But it could be modified to work on the 300, if you can live without the choke.

Or with some work and some cash you could instal a choke set up on it. You'd have have to drill a couple holes for the choke butterfly shaft. But otherwise all the mounting holes are there.

It's pretty cheap too compared to most new carbs too.

http://www.summitracing.com/parts/hl...6/media/images

Mar 26, 2013 | 09:20 PM

#17

68cabby

Thread Starter

Laughing Gas

Joined: Aug 2011

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Ah yes..the Econimizer carb I believe is what it was called? Seen a few around. Might be a good approach to take also. While ice been doing research..I know I have several options. The carb you mentioned for example..a 570 cfm street avenger ( thinking strongly about this one) I have one locally going for cheapish.
I do have a couple questions I've never thought of before.
1. Since I'm running a C intake..would a spreadbore type carb be an option? I hear bad things of using a spread to square adapter and was curious if I happen to look at spreadbore types if is need an adapter?

2. I noticed a lot of Holleys vacuum secondary setups use just 1 fuel inlet. Unlike the dps which use 2 to supply the secondaries. The street avenger series even though a vacuum secondary carb has a duel fuel inlet design. What's the point of this? Is there advantages or disadvantages to either design?

Mar 26, 2013 | 09:56 PM

#18

Harte3

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Joined: Dec 2006

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From: Spokane, WA

The Economizer is a 4350 series at one time made by Holley to replace Qjets. Small primaries and IIRC 2" secondaries.

Mar 27, 2013 | 02:13 PM

#19

68cabby

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Laughing Gas

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Seems like ill never make to my mind. I just wanna make sure I get it right the first time. Carbs can be a lot of money and affect a lot in the stability of a good running engine. Maybe I'm just being swayed too much by reviews or something..I want something I can tune and run on the engine well.

Mar 27, 2013 | 04:37 PM

#20

68cabby

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Laughing Gas

Joined: Aug 2011

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Well fellas..I took the plunge. Went ahead and decided to go with a 570 cfm holley street avenger..aluminum.
Why did I decide? Well..the new aluminum models address some of the old issues of the regular street avengers. They're pretty much an Ultra Street avenger but without the cool colors and what not.
The carb is a vacuum secondary with a quick change spring system sinuous can dial how fast the secondaries open up. Big plus! The new aluminum models also offer 4 corner idling. I like the fact that it has 2 fuel bowls so I can dial in the secondaries if need be. This carb is advertised as an awesome carb for high torque application while maintaining a good top end too

Mar 28, 2013 | 06:49 PM

#21

Rusty_Old_F250

Fleet Mechanic

Joined: Aug 2009

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From: Western Washington

Hi Jesse,

I've got the regular version of the street avenger on my 390.

The only complaint I have is it's a little more difficult to make it idle nice and smooth. It's much more sensitive than the last carb (500 2bbl) But I think the 4 corner idle might help with that.

It definitely builds a lot of low end torque!

Sam

Mar 28, 2013 | 08:08 PM

#22

68cabby

Thread Starter

Laughing Gas

Joined: Aug 2011

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That's why I chose the newer aluminum versions. It seems that holley went ahead and updated the old design with them. They're like an "in between" between the ultras (I drooled at) and the old zinc versions. I was doin some reading on em and it seems like a lot of people had problems with off idle stumble. Due to what? Idk.
Hopefully it'll do great on my 300

thanks Sam!

Mar 29, 2013 | 11:16 AM

#23

Rusty_Old_F250

Fleet Mechanic

Joined: Aug 2009

Posts: 1,771

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From: Western Washington

Funny that you mention an off idle stumble, I had that issue with it at one point. It seemed to be a bit of trash in the accelerator pump squirter, but even once I cleared it out it still had a mild stumble. Never figured out what caused it and it runs good on the new engine.

Sam

p.s. Don't want to hijack the thread, but we need pics of those seats in your truck!