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Still chipping away at it. For 2021, my best was 9.15/145.6 (3600#) For 2022 it ran a 9.11/146.1
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I think there might be just a little left in it but been fighting a carb fuel slosh issue ever since the car has been launching wheels up and got down in the 1.27-1.32 range. This Video of my new PB, you can hear the car bog off the line. This is as good as I can tune the carbs. Don't know what that bog would be worth but it has to be something. Tried everything I can think of; between 4-7psi fuel pressure, float levels, rubber vent connector hoses, etc. Some settings have been an improvement but nothing perfect and I'm done trying to make them work. This Video is one with the fuel pressure set at 7psi which I knew was the wrong way to go but had to try. It left hard off the brake and literally flooded out quickly during the wheelie, so bad it barely finished the pass down the track. I know there are carb metering blocks designed to fix this issue but they'd cost almost as much as these carbs did, so I'm done with them.

Had been thinking of going to the dark side with EFI, took the advise of a TC member and bought the Holley Terminator X Stealth 2x4500. It's throttle body injection but has the stand-alone ECU. Hopefully this will eradicate fuel issues and possibly get me my goal of an 8.99 pass on this engine and as a bonus, make the car a little more friendly around town. I'll be updating the thread I started in the EFI section with the install. Looking forward to being a laptop tuner and not having to get my hands gassy smelling :)

Happy 2023!!
 

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Still chipping away at it. For 2021, my best was 9.15/145.6 (3600#) For 2022 it ran a 9.11/146.1
View attachment 758912
I think there might be just a little left in it but been fighting a carb fuel slosh issue ever since the car has been launching wheels up and got down in the 1.27-1.32 range. This Video of my new PB, you can hear the car bog off the line. This is as good as I can tune the carbs. Don't know what that bog would be worth but it has to be something. Tried everything I can think of; between 4-7psi fuel pressure, float levels, rubber vent connector hoses, etc. Some settings have been an improvement but nothing perfect and I'm done trying to make them work. This Video is one with the fuel pressure set at 7psi which I knew was the wrong way to go but had to try. It left hard off the brake and literally flooded out quickly during the wheelie, so bad it barely finished the pass down the track. I know there are carb metering blocks designed to fix this issue but they'd cost almost as much as these carbs did, so I'm done with them.

Had been thinking of going to the dark side with EFI and took the advise of a TC member buying the Holley Terminator X Stealth 2x4500. It's throttle body injection but has the stand-alone ECU. Hopefully this will eradicate fuel issues and possibly get me my goal of an 8.99 pass on this engine and as a bonus, make the car a little more friendly around town. I'll be updating the thread I started in the EFI section with the install. Looking forward to being a laptop tuner and not having to get my hands gassy smelling :)

Happy 2023!!
That's one cool car!!! I cannot say I blame you for wanting to go to the dark side. That being said, I just wanted to ask you this: Have you tried using jet extensions in the secondary fuel bowl? I'm gonna guess that you have, but you didn't mention that in your post. One of the reasons I asked you that is that I was amazed that when I bought a professionally tuned Dominator carb from AED Performance, I asked the guy when I placed the order if he would be installing jet extensions, and he said no unless I wanted them. I told him that I did, and the carb came with them like I specified, but I was left with the impression that it wouldn't have had them if I didn't make mention of that. Of course I could've easily put them in myself, but I was a little puzzled as to why he doesn't automatically include them. Anyway, I hope this helps, although it sounds like you've already made the decision to try out the F.I. I wish you the best either way. (y)
 

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That car is rad. Love it.
 
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1971 Chevelle. Carb’d 6.0 LS Th350 3.90 12 Bolt. 1972 Greenbrier Wagon 489, 700r4 3,73 12 bolt
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See if your carb has the short vent whistle. My 850 hp had it and took me forever to figure out. Put the longer one in and finally fixed the launch bog issue I was having.
 

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Wicked car. 7 PSI shouldn't have caused a problem. Hope you hit that 8.99!
 

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Discussion Starter · #7 ·
That's one cool car!!! I cannot say I blame you for wanting to go to the dark side. That being said, I just wanted to ask you this: Have you tried using jet extensions in the secondary fuel bowl? I'm gonna guess that you have, but you didn't mention that in your post. One of the reasons I asked you that is that I was amazed that when I bought a professionally tuned Dominator carb from AED Performance, I asked the guy when I placed the order if he would be installing jet extensions, and he said no unless I wanted them. I told him that I did, and the carb came with them like I specified, but I was left with the impression that it wouldn't have had them if I didn't make mention of that. Of course I could've easily put them in myself, but I was a little puzzled as to why he doesn't automatically include them. Anyway, I hope this helps, although it sounds like you've already made the decision to try out the F.I. I wish you the best either way. (y)
See if your carb has the short vent whistle. My 850 hp had it and took me forever to figure out. Put the longer one in and finally fixed the launch bog issue I was having.
Thanks, I didn't want to get into everything I've tried with the carbs but will say the jets don't have extensions because they're mounted sideways and have a different dynamic in respect to fuel slosh than typical mounted carbs. I've also tried long, short vent whistles, even removed them. Again, because carbs are mounted sideways, it didn't have any impact on the fuel slosh. There's not once in the last 3yrs, going to the track that I haven't tried something different. I found settings that improved things, but never fixed it completely. Doesn't really matter because I'm all in on the EFI now. Being able to log anything the system monitors, will be a huge bonus.
 

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Discussion Starter · #8 ·
Wicked car. 7 PSI shouldn't have caused a problem. Hope you hit that 8.99!
Thanks! 7psi was actually the worst for these carbs. It worked best around 4.5. I've tried so many things, just don't want to type it all out. Doesn't really matter. Now I'm going to be one of those guys, sprawled across their roofs, hugging their laptops after every run:)
 

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Thanks, I didn't want to get into everything I've tried with the carbs but will say the jets don't have extensions because they're mounted sideways and have a different dynamic in respect to fuel slosh than typical mounted carbs. I've also tried long, short vent whistles, even removed them. Again, because carbs are mounted sideways, it didn't have any impact on the fuel slosh. There's not once in the last 3yrs, going to the track that I haven't tried something different. I found settings that improved things, but never fixed it completely. Doesn't really matter because I'm all in on the EFI now. Being able to log anything the system monitors, will be a huge bonus.
AAAAAHHH....OK...yeah I figured by the looks of your car in the video that you have dual quads, and maybe a tunnel ram too, but I was overlooking the probability of you having carbs mounted sideways. Yeah, the jet extensions wouldn't matter in that case. Thanks for the clarification on that. (y)
 

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After going from a carb to a sniper deal, all I could think is how much money I wasted on carbs I could have bought a multi port injection kit. So much better and consistent!
 

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Get some 130 needles and seat form BLP and then reset your pressure to 4.5psi the bigger seat will keep fuel foaming down. What chip do you leave off the trans brake? It is also possible you need more converter (that's what it sounds like to me) I know tunnel rams can be tough to tune but you could always switch to a single 4bbl setup for a test. Just throwing a few possibilities out there for you. Nice run though.
 

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Please don't take this the wrong way. Your car is fast and powerful. And I for one think it's impressive what you've accomplished with it already. But I'm wondering if your engine just isn't making enough power for the weight of the car, in order to turn the high 8 second ET. So my guess here is that you'll either need to look to trim some weight, or increase the power level. The only other thing I can think of is if the torque converter is every thing you need it to be, along with te stall speed being optimal. Just food for thought.

The comparison in post #10 might not be applicable due to that being a forced induction application while yours is naturally aspirated. But that's just a guess on my part
 

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One BADASS 66 !
I've heard some good suggestions here but I'll add another possibility that I've seen/used first hand in a similar situation. Off line semi bog . Whatever the cause the issue Is a very brief moment where there's not enough fuel there and results in a lean bog . Obviously. . Extensions or longer whistle as already mentioned could be it . I fought with one that was acting similar. Did everything .
Up with squirters. Down with squirters.
Used a wide variety of different color cams along with different combinations of squirters. No dice .
Finally the very last thing I did which id thought of early on but figured wasn't the problem mostly because of advice I was taking actually WAS the problem.
Bigger squirters do increase volume but slow the rate/duration of the delivery. The opposite goes for smaller squirters but the ammount of fuel available in either case Is dictated by the size of the pump bladder .
When the throttle is stabbed very quickly
there is a whole lot of air being thrown at the engine especially in the case of a high cfm carb(s) . Hence the potential of the fuel not catching up quite as quickly as necessary. . Doesn't take much for a problem .
Increasing the ammount of fuel available out of the pump bladder can be the solution and was the solution in my case . And BTW everyone I turned to for advice suggested that this more than likely was not the issue.
It was the issue .
I switched from the 30cc pump bladder to the 50cc bladder and that was it . Zero hesitation. On the planes of hesitation lay the bleached bones of countless millions 😁😎
 

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Thanks, I didn't want to get into everything I've tried with the carbs but will say the jets don't have extensions because they're mounted sideways and have a different dynamic in respect to fuel slosh than typical mounted carbs. I've also tried long, short vent whistles, even removed them. Again, because carbs are mounted sideways, it didn't have any impact on the fuel slosh. There's not once in the last 3yrs, going to the track that I haven't tried something different. I found settings that improved things, but never fixed it completely. Doesn't really matter because I'm all in on the EFI now. Being able to log anything the system monitors, will be a huge bonus.
Yeah but it's not a carb then . You can get er done with a carb . Sounds like you already pulled the EFI lever though. Nothin wrong with that .
 

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Have you tried the angled floats. They had them years ago for tunnel ram carbs to deal with being sideways. And I found 6 psi was all my carb needed. Anything more aerated the fuel.
 
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Still chipping away at it. For 2021, my best was 9.15/145.6 (3600#) For 2022 it ran a 9.11/146.1
View attachment 758912
I think there might be just a little left in it but been fighting a carb fuel slosh issue ever since the car has been launching wheels up and got down in the 1.27-1.32 range. This Video of my new PB, you can hear the car bog off the line. This is as good as I can tune the carbs. Don't know what that bog would be worth but it has to be something. Tried everything I can think of; between 4-7psi fuel pressure, float levels, rubber vent connector hoses, etc. Some settings have been an improvement but nothing perfect and I'm done trying to make them work. This Video is one with the fuel pressure set at 7psi which I knew was the wrong way to go but had to try. It left hard off the brake and literally flooded out quickly during the wheelie, so bad it barely finished the pass down the track. I know there are carb metering blocks designed to fix this issue but they'd cost almost as much as these carbs did, so I'm done with them.

Had been thinking of going to the dark side with EFI, took the advise of a TC member and bought the Holley Terminator X Stealth 2x4500. It's throttle body injection but has the stand-alone ECU. Hopefully this will eradicate fuel issues and possibly get me my goal of an 8.99 pass on this engine and as a bonus, make the car a little more friendly around town. I'll be updating the thread I started in the EFI section with the install. Looking forward to being a laptop tuner and not having to get my hands gassy smelling :)

Happy 2023!!
Congrats Monk!!!!!!!!
 

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Thanks, I didn't want to get into everything I've tried with the carbs but will say the jets don't have extensions because they're mounted sideways and have a different dynamic in respect to fuel slosh than typical mounted carbs. I've also tried long, short vent whistles, even removed them. Again, because carbs are mounted sideways, it didn't have any impact on the fuel slosh. There's not once in the last 3yrs, going to the track that I haven't tried something different. I found settings that improved things, but never fixed it completely. Doesn't really matter because I'm all in on the EFI now. Being able to log anything the system monitors, will be a huge bonus.
hey , shuttap and get that laptop plugged in man. :) Oh EFI SCARES me, to be sure. But hope you commit 100%, get really good with tuning in short order, and WITH YOUR WHEELS UP Blow past < 9.00

I recall member Doug Flynn ( Holley) went racing with EFI years back when it was truly novel.
 

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Not sure but I must have worded my opening post wrong. Never meant to make this about how to fix the carbs. They were so yesterday :)

A little back story...my 502 grew into a 540 in '18. Didn't realize it's been that long. The bigger engine started out with a sniper jr and a conventional mounted AED 1050. Of course wanted to go faster, switched to an Edelbrock 2R tunnel ram with 2-1050's, then a Foxwell ported Dart tunnel ram. As it got quicker with the tunnel rams, this fuel slosh issue showed up. Over the last 5 years, I've tested/used different things; a couple different cams, different ignition systems, air cleaners, a carb scoop, dead head regulator, return style regulator, switched to angle floats, tried 3 different style needle/seats (there is no foaming, have video running on dyno), many different float levels, main & idle air bleed/jet combo's, etc. You name it, I've probably tried it. Slicks and radials, trans brake or foot brake didn't matter. It all boils down to when the car started '60 footing well along with the front end up. The issue is not present on the chassis dyno (which I have many sessions on), only at the track. I suspect what was happening is initial g-force along with a tilted carb during a wheelie, uncovered the "front" jets. I could raise fuel level to compensate but then it would mess with the fuel curve. That first video of my new best, is a compromise of fuel pressure and bowl levels to get a "clean-ish" run. It's a lean bog that appears as a convertor issue, but it's not.

Anyways, I learned a lot about carbs but am just ready for something different. Although I appreciate everybody's carb suggestions, the Stealth Throttle Bodies are bolted on now and carbs are for sale. I won't be going back to them in my lifetime.
 
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