race veterans plz help!!!!!!!

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bignasty123

bignasty123

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well my car is a 408 hydralic cam eddy head.motor 904 3500 convertor 3.91 gears..hooks perfect....

my car weighs 2900 with me in it.. this weekend we raced it it ran 13 flat...it has a holley street avenger carb 770....it would hesitate and bog as soon as u went wot and it just didnt run well at all...fyi i ran a 12.3 with stock small fuel system..changed to 3/8th and have a mechanical pump a good one tho..how do i improve my 2.6 60 foot..what can i do to the carb i have to make it better ..or what one should i buy any info would help plzplz input
 
I beleive the Street avenger is a vacum sec. carb No?You could try changing out the secondarie spring(different colors)which will change when your sec. open.Now for my 408 I race with,I run an AED850DP(modified holley)which Summit now carrys for a reasonable price IMO.I bolted it on right from the get go and ran 11.20@121mph,now my best has been 10.81@124 60fts 1.50.Now my engine setup is different than yours,so need more info on your setup.
Ignition(MSD)?
Intake and cam
Tire size The 2.6 60 fts sounds like it,s falling flat on it,s face.
 
You have either to much squirt from your acc. pump and its flooding or to little and its running out of fuel before the main circuit kicks in. What size squirters are you using. What kind of tires. What RPM did you launch at. Give us more info on your combo.
 
Wow! Something is SERIOUSLY wrong....your car should be at LEAST in the low 12's to high 11's. Those 60' times are dismal.

Do you have another carb you can borrow?
Check for vacuum leaks?
What MPH are you running in the 1/4?
What do your plugs look like?
Timing?

Sorry, kind of hard to diagnose over the internet without a LOT of details. More than likely it is just a carb/fuel issue....but you never know.
 
tires is 26 high 13.5 wide mt slick..no traction issues..ran a 35 squriter and a 45 it picked up but im telling u as soon as u went wot it fell on its face and took like 1/4 to pick up then it was a beast...but that is our problem..i dont want to play games with this vac sec carb it blows....what should i look at and can ig hughes hydralic 567 lift..that csan falls on ots face around 6100 also..we are going thru the traps at 5700 little fyi...i want to run a mp 296 557 cam would that be better for my combo
 
can you borrow a carb that's working? Taller tires might help your trap RPM, You don't give cam duration but the 2 lifts are comparable.
I still think you have a carb. problem
 
bignasty123 said:
tires is 26 high 13.5 wide mt slick..no traction issues..ran a 35 squriter and a 45 it picked up but im telling u as soon as u went wot it fell on its face and took like 1/4 to pick up then it was a beast...but that is our problem..i dont want to play games with this vac sec carb it blows....what should i look at and can ig hughes hydralic 567 lift..that csan falls on ots face around 6100 also..we are going thru the traps at 5700 little fyi...i want to run a mp 296 557 cam would that be better for my combo
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First off, what, exactly, has changed from when you ran the 12.3 to the 13 flat? Is the carb new or did it run the 12.3 on this carb?

You really should not need a squirter that big. I'd recommend that you go back to the squirter that came with the carb, which is probably a 28 or 31, and go to a stiffer secondary spring. I'm guessing that the secondary spring is too soft and is basically flopping open, causing a bad bog. Holley secondary springs are cheap and easy to change.
 
I would also say carb probs.
I would try to borrow one to try it out.

My first Holley was an old 850 double pumper.
I put it on my 440 with a 509 can.
Took a few evenings to sort out someone elses mess.
Had to change the pumps and ramp speed for the secondaries.
Then of course the squirters and jets.

I left the tree from idle and not bog.
I know many people think it is crazy when I tell them, but when they see me leave the line, they believe.
 
possibly running out of fuel? do you have a pressure gauge on it? if you have an electric pump, bypass the mechanical and see if that makes a difference. what psi is the new fuel pump? does it pop or just lay down? does backing of the pedal pick up the power again?
 
Assuming you're getting enough fuesl, I think "pettybluedart" gave you the best answer.
While a trick carb is grea , you can make the best of what you got & in this case, again I think he gave you a good answer. I'm curious-what do the plugs look like? If it were me, I'd find a quiet place & launch the car a few times & immeditaely shut it off & read the plugs. Once you know what the cylinders are "seeing" you'll know which way to go with the carb settings.......
 
yea somthing wrong, my HYD. 318 with X heads on pump gas went 12.23 at 109, I wouldnt be to happy with those #'s from a 408, I would try a different carb, thats a good starting point
 
hemicop said:
Assuming you're getting enough fuesl, I think "pettybluedart" gave you the best answer.
While a trick carb is grea , you can make the best of what you got & in this case, again I think he gave you a good answer. I'm curious-what do the plugs look like? If it were me, I'd find a quiet place & launch the car a few times & immeditaely shut it off & read the plugs. Once you know what the cylinders are "seeing" you'll know which way to go with the carb settings.......
Click to expand...

This is golden information right here. Like hemicop says, pettybluedart gave some great information. But I would want to know exactly what the plugs are seeing.
One rule I learned about drag racing that served me the best, "lean is mean!" When you start seeing little sparkles (piston) on the plugs after a pass, you need to fatten it up a little. :D
 
thank you for all the replys..its the same carb i ran the 12.3 with....im gonna go with the spring kit first and then what next? what jets would u guys suggest i have read alot and tinckered with some carbs. i just wanted some good advicce from alot of ppl books arent on the track on the weekends like us pepole have better in fo then a book j...thats just me..so ill get he springs and im runnign the softes spring so im gonna hve to go stiffer and then see. also what size squriter should i go with im gonna test and tune in aug and i wqant to have all the right stuff on hand so we can make adjustments at the track.thanks again
 
One thing I haven't seen mentioned, what is your total timing? This was always a big deal with me, had to have 44 degrees.
 
First thing I would do is check for a vacuum leak. Fire the car up and let it idle. Spray some carb cleaner around all the (intake & carb) gaskets and hoses to make sure you don't have any leaks. If you have vacuum hoses going to the carb that you aren't sure what is for, remove the hose and plug the port on the carb/intake. If you are running a PCV check and make sure it is working correctly. It should suck closed at an idle (high vacuum). If you are sure there are no vacuum leaks, the next thing I would suspect is you got some debris in the carb when you changed the fuel lines. Turn the engine off and look in the carb. Pull on the throttle cable and check for a nice steady stream of fuel from the the shooters. You should see the stream start as soon as you even think about pulling on the throttle. If the stream hesitates or looks uneven between the shooters, you probably have soem debris stuck in the accelerator pump passeges.

If everything still looks good, I would drop the shooter size back to the 35 you had before and see what it does.

All of the above assumes you have good time with 15 initial and 20 mechanical in the distributer.
 
ok. i'm sure that when you get bigger than a .045" squirter you have to go to a 50cc pump. first make sure you have the correct clearance at the pump linkage at wot. second make sure the pump cam is in the #1 hole. third you can try different pump cams to see if that helps. you mentioned that you have the lightest secondary spring in, what you are looking for is to NOT feel the seconderies open when you have the correct spring installed. so keep going to a next stronger spring until the shutter stops.

what are you using for a fuel pump and sizes of the fuel lines from the tank to carb?

like hemied mentioned and what is initial timing set at?
 
Fuel not being delivered by the secondaries, or barely. Rear float level issue. Rear fuel flow. My guess.
 
Yeah, he is leaving a whole second at the 60' mark compared to my dismal 60' and I only have a 2500 stall. Why not borrow a 750 or 830 doublepumper flattop and see if you problem gets fixed.
 
Found the problem my cam was flattened out......lol so time isn't bad considering...now I'm going ported eddy heads mopar 590 cam and bigs 750 dp so hope it picks up which I know it will
 
Why not also get an elec pump plumber into the 3/8 line while you are at it? My car does just fine with a 292H purple 508 cam and an 830 flattop... will that 750 be enough for your stroker?
 
Yeah, flat lobes tend to cause a stumble. Glad you figured it out, too bad it wasn't something minor.

If you're doing a lot of racing with it, you might want to go with an 850. The Holley HP series carbs are great.
 
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