604 stumbles.. Please HELP!!

we have a factory sealed 604. I have purchased two carbs the latest is 650 cfm from Holley. we are running e85 from ignite . it has been tested so right on 85 . we have changed fuel lines msd boxes. distributor plugs. went to little colder plug for e 85 . replaced switches battery . There really isn't anything we haven't changed. this page is new carb we purchased http://www.holley.com/0-80842HB.. As you can see you can change anything on it . Trust me we have. It is a bad stumble from idle circuit . Restarts and running low is bad. If we run high keep up rpm no issue. Runs good numbers. I been racing for years never had an issue like this . Nothing helps . running a vacum gauge but seems to take a long time for vacum to drop . Has anyone had this experience. I could scream . any help at all would be so grateful . on idle it has almost 20psi vacum Only experience in high hp motors so the vacum is more then i am use to dealing with.

You know about the polarity of the distribute pickup? Purple wire NOT going to black wire with purple tracer?

Quote:

---

Originally Posted by tworrick

we have a factory sealed 604. I have purchased two carbs the latest is 650 cfm from Holley. we are running e85 from ignite . it has been tested so right on 85 . we have changed fuel lines msd boxes. distributor plugs. went to little colder plug for e 85 . replaced switches battery . There really isn't anything we haven't changed. this page is new carb we purchased http://www.holley.com/0-80842HB.. As you can see you can change anything on it . Trust me we have. It is a bad stumble from idle circuit . Restarts and running low is bad. If we run high keep up rpm no issue. Runs good numbers. I been racing for years never had an issue like this . Nothing helps . running a vacum gauge but seems to take a long time for vacum to drop . Has anyone had this experience. I could scream . any help at all would be so grateful . on idle it has almost 20psi vacum Only experience in high hp motors so the vacum is more then i am use to dealing with.

---

You'll probably fight that until you get a carb directly from someone that knows how to build one for E-85 on a 602 or 604. JDR, Stealth, maybe Willy's.

Quote:

---

Originally Posted by jedclampit

You know about the polarity of the distribute pickup? Purple wire NOT going to black wire with purple tracer?

---

Yes we also checked that issue.

Quote:

---

Originally Posted by 50j

You'll probably fight that until you get a carb directly from someone that knows how to build one for E-85 on a 602 or 604. JDR, Stealth, maybe Willy's.

---

this carb is specific to e85. there is nothing that can't be changed. They use the exact same metering block . They all come from Holley.

No and no, but good luck with it.

Quote:

---

Originally Posted by tworrick

this carb is specific to e85. there is nothing that can't be changed. They use the exact same metering block . They all come from Holley.

---

holly does not have a good E-85 program yet. we build our own. you need 50cc pumps on both sides 41 front and 47 rear shooters with the big yellow cams. that is what we have found to work the best.

I'd reduce the size of the primary squirter and try that.

Quote:

---

Originally Posted by tworrick

we have a factory sealed 604. I have purchased two carbs the latest is 650 cfm from Holley. we are running e85 from ignite . it has been tested so right on 85 . we have changed fuel lines msd boxes. distributor plugs. went to little colder plug for e 85 . replaced switches battery . There really isn't anything we haven't changed. this page is new carb we purchased http://www.holley.com/0-80842HB.. As you can see you can change anything on it . Trust me we have. It is a bad stumble from idle circuit . Restarts and running low is bad. If we run high keep up rpm no issue. Runs good numbers. I been racing for years never had an issue like this . Nothing helps . running a vacum gauge but seems to take a long time for vacum to drop . Has anyone had this experience. I could scream . any help at all would be so grateful . on idle it has almost 20psi vacum Only experience in high hp motors so the vacum is more then i am use to dealing with.

---

Was this motor already in the car running good and then you changed two carbs??

It is a bad stumble from idle circuit, meaning in the shop?

Restarts and running low is bad, meaning stumbles then gets going?

Guess would be the accelerators too rich. Remove the secondary acc. arm and try it. Quick track fix on a 4 bbl.

That line of carbs is not crate friendly. That carb could run on a 400 HP motor with a 106 LC and you don't run the same power valves, acc pumps, main metering wells etc. You answered your own question, different vacuum map.

Quote:

---

Originally Posted by DaveBauerSS6

Was this motor already in the car running good and then you changed two carbs??

It is a bad stumble from idle circuit, meaning in the shop?

Restarts and running low is bad, meaning stumbles then gets going?

Guess would be the accelerators too rich. Remove the secondary acc. arm and try it. Quick track fix on a 4 bbl.

That line of carbs is not crate friendly. That carb could run on a 400 HP motor with a 106 LC and you don't run the same power valves, acc pumps, main metering wells etc. You answered your own question, different vacuum map.

---

No motor never has run from start. Yes on restarts it stumbles like nothing no response at all . then it takes off and is good . unless you put it under heavy load . Like on a tacky track running low. off accelerator. In the shop sounds great . even in take off gear revs up nice . soon as you shift into high you under load you can feel it. then when you apply gas it falls flat. Then like when power valve or getting out of idle circuit it takes off and is fine . a engine builder told us to go down on squirter size. to 28 . and that did't help . we have been both sides trying to add more fuel and or lean it out .

Quote:

---

Originally Posted by twisterf5

holly does not have a good E-85 program yet. we build our own. you need 50cc pumps on both sides 41 front and 47 rear shooters with the big yellow cams. that is what we have found to work the best.

---

that is what I wish someone cold be tell me . Is it lean or rich ,as you can see different opinion on more fuel or less. I haven't gone as far you guys did . I did try two 50 cc pumps with both having 42 shooters. I believe both had pink cams .

Put the whole deal in a box and send it to Tony at Stealth or John at JDR and when it comes back bolt it on and don't touch it

there is more to the equation than most think

Brad

Quote:

---

Originally Posted by brad hibbard

Put the whole deal in a box and send it to Tony at Stealth or John at JDR and when it comes back bolt it on and don't touch it

there is more to the equation than most think

Brad

---

Do they actually dyno them> or do they just have a standard set up for crate?

Find someone that will let you try a carb you know is good. Do it after the races one night to see if its the carb for sure.

now there is some good advice