Holley 850 street HP pukes off the line

[BSB67]

the only issue is why did he have a vacuum leak with 2 carbs he owned but didnt have the same vac leak with the borrowed carb? if it was a massive vac leak that was unrelated to the carb, it would still be there with the borrowed carb. unless he has an open port on the carb base that was blocked off on his borrowed carb.

check all holes plugged on the carb base.

Agreed. Kinda seems unlikely, and obvious. But you cannot assume the knowledge level of posters. And he is missing something, or failing to share a pertinent detail. There are different bases, base gaskets, and we don’t know if a spacer is being used, or a PVC.

I think we’re all grabbing at straws for the information provided.

 

[JackBEEQuick]

Precisely. It’s the one that worked flawlessly that keeps ruling out Anything else besides carburetor issue.
Technically I’ve used a total of 4 different 850s , a new XP (ouch) a new HP (less ouch) , a borrowed 850 pro form , and a borrowed well seasoned Holley 850 that he paid $20 for lol of course that one rocked..

What’s more puzzling is that 850 pro form from guy A, works amazing on guy Bs roadrunner, whose is very similar to my 440… so we thought for sure the pro form would work on mine, but no it was same result.

Idle vacuum I’m at 15psi about 3/4 turns on all idle screws …
I can’t say for certainty all the inlets are blocked but I will verify that.

 

[BSB67]

Did you also ditched a 6 pack that was not running right?

 

[BSB67]

Any answers to the questions in #14?

 

[JackBEEQuick]

Agreed. Kinda seems unlikely, and obvious. But you cannot assume the knowledge level of posters. And he is missing something, or failing to share a pertinent detail. There are different bases, base gaskets, and we don’t know if a spacer is being used, or a PVC.

I think we’re all grabbing at straws for the information provided.

using the gasket that came with the Holley , no spacer. trick flow track heat intake , and yes on the pvc

 

[JackBEEQuick]

How does it idle?

How does it cruise at 50 mph?

Is your testing wot on the street, or track only?

Have you visually verified that both the front and rear squirters are functioning fully/properly ?

Idles great, cruises great, tested WOT on street and track, same results.
I can visually see the primary squirter sprays excellent , I can’t confirm the secondary by myself.
Before the I put the yellow cam in it would just kind of dribble until I was a short ways into the pedal, with the yellow cam it was instant spray with a tap of the peddle. Lookin at the pump cam graph the blue looks to carry the closest lift to the yellow cam but then tapers off, I thought about putting the blues back on and could see if that cuts back the fuel dumping in while maintaining launch

 

[JackBEEQuick]

Did you also ditched a 6 pack that was not running right?

I have the six pack on the shelf , will likely sell that.

 

[furious70]

Buying your buddies carb seems to be your best bet!
Joking aside I'm out of ideas.
Did the 6 pack do the same thing?

 

[hunt2elk]

Buying your buddies carb seems to be your best bet!
Joking aside I'm out of ideas.
Did the 6 pack do the same thing?

Lol, I was just going to ask if he could buy the good running carb from his buddy.

 

[RemCharger]

Lol, I was just going to ask if he could buy the good running carb from his buddy.

Reminds me, way back we all went to a dyno day and my cousin ran his 440 with an 850 demon. Somewhat disappointing so the store owner asked if hed like to try a new 1050 4150. Didn't it just run great and picked up 50 horse. He even drove it around and it was perfect.
The guy said pull off my dyno carb and ill get one coming for you.
Nope. Cuz wasn't leaving without THAT carb on his motor...

 

[Texas97]

Precisely. It’s the one that worked flawlessly that keeps ruling out Anything else besides carburetor issue.
Technically I’ve used a total of 4 different 850s , a new XP (ouch) a new HP (less ouch) , a borrowed 850 pro form , and a borrowed well seasoned Holley 850 that he paid $20 for lol of course that one rocked..

What’s more puzzling is that 850 pro form from guy A, works amazing on guy Bs roadrunner, whose is very similar to my 440… so we thought for sure the pro form would work on mine, but no it was same result.

Idle vacuum I’m at 15psi about 3/4 turns on all idle screws …
I can’t say for certainty all the inlets are blocked but I will verify that.

that seems awfully lean on the idle screws. im at 13.5 merc-inches and almost a full turn further out on all 4 corners than you are.

are you sure you're rich because your mixture screws, in my opinion, say you're lean.

15 idle vacuum and its sucking lots of air and not enough go juice when it needs it.

if it were me, id use a vac gauge to set the idle mixture OR set all of them at 1 and 3/4 turns out and start adjusting a quarter turn at a time until it gets happier.