Any Holley Ultra Double Pumper Guru's ?

[TEXANOW]

Update: I removed carb and pulled it down, changed power valve back to 6.5 now that I'm getting 13" of vacuum. Jets are now 70 on the primary's and 73 on the secondary's Drilled all 4 butterflies with .130 drill bit. Now idling with 15" of vacuum. Idle screws have a profound effect on the idle. They are adjusted out 1 1/4 turns now. I haven't changed a plug yet to see what it looks like since I changed the setup. I am waiting for it to cool down now. I think this did the trick. I still need to look at the timing again and see if I can back it down some. I set the floats first thing. Thanks guys for taking the time to consider my problem. I hope this helps someone else that might be having the same problem. I will update this thread with any new info. Thanks again.

HELLO SCACER 1.  HOPING YOU HAVE THINGS SORTED OUT WITH YOUR CARB.  I PLAN ON USING THE SAME HOWARDS CAMSHAFT AND A 750 OR 780 HOLLEY 4150 SERIES OF SOME SORT.  I WAS WONDERING IF YOU HAVE BEEN ABLE TO "TRY OUT" YOUR COMBO YET, AND HOW IT PERFORMS.  I WILL BE USING MINE IN A 73 COUGAR CONVERTIBLE, C6 2500-3000 STALL 3.89 GEARS.  THANKS!

 

[scacer1]

Update: I removed carb and pulled it down, changed power valve back to 6.5 now that I'm getting 13" of vacuum. Jets are now 70 on the primary's and 73 on the secondary's Drilled all 4 butterflies with .130 drill bit. Now idling with 15" of vacuum. Idle screws have a profound effect on the idle. They are adjusted out 1 1/4 turns now. I haven't changed a plug yet to see what it looks like since I changed the setup. I am waiting for it to cool down now. I think this did the trick. I still need to look at the timing again and see if I can back it down some. I set the floats first thing. Thanks guys for taking the time to consider my problem. I hope this helps someone else that might be having the same problem. I will update this thread with any new info. Thanks again.

HELLO SCACER 1.  HOPING YOU HAVE THINGS SORTED OUT WITH YOUR CARB.  I PLAN ON USING THE SAME HOWARDS CAMSHAFT AND A 750 OR 780 HOLLEY 4150 SERIES OF SOME SORT.  I WAS WONDERING IF YOU HAVE BEEN ABLE TO "TRY OUT" YOUR COMBO YET, AND HOW IT PERFORMS.  I WILL BE USING MINE IN A 73 COUGAR CONVERTIBLE, C6 2500-3000 STALL 3.89 GEARS.  THANKS!

Sorry I haven't posted in awhile. Got frustrated and gave up on it. The plan at this point is to drill the butterflies to .150, and add the wire restrictors, then go up 1 step hotter on the plug. The headers are open right now and at this point I am wondering if I have a reversion problem. Any thoughts? :huh:

 

[mustang7173]

scacer1,

How old is that carburetor? I have had Holley's tuned and tuned just to discover that they had internal cracks causing vacuum leaks. If your budge allows, chunk the Holley and get you a FiTech system. I have the FiTech Go 400 and just love it!

https://fitechefi.com/products/30021/

 

[scacer1]

scacer1,

How old is that carburetor? I have had Holley's tuned and tuned just to discover that they had internal cracks causing vacuum leaks. If your budge allows, chunk the Holley and get you a FiTech system.  I have the FiTech Go 400 and just love it!

https://fitechefi.com/products/30021/

Brand New out of the box. The Holley Ultra series uses billet aluminum metering blocks so I don't think that is the problem (Although there could be an internal crack in the main body). Also I put a different carb on it and it is still fouling the plugs. That is why I am thinking that this is a reversion problem. I would rather try to get this tuned than to chuck a brand new carburetor, but it may come to that if I cant get this tuned right.

 

[Don C]

It's my experience that open headers cause a lean condition. How long are you running it and at what RPM before you read the plugs?

 

[scacer1]

It's my experience that open headers cause a lean condition. How long are you running it and at what RPM before you read the plugs?

I haven't gotten it out on the the road yet, I am trying to get it so that it wont foul the plugs at idle. The reason I am thinking it is a reversion problem is the cam has a 108 degree LSA so it has a lot of overlap. I might have to go out and run it hard to see if that cleans up the plugs. I know that high performance carbureted cars in the past would foul plugs at idle but once they were opened up the plugs would clean up and run hard.

 

[mustang7173]

scacer1,

How old is that carburetor? I have had Holley's tuned and tuned just to discover that they had internal cracks causing vacuum leaks. If your budge allows, chunk the Holley and get you a FiTech system.  I have the FiTech Go 400 and just love it!

https://fitechefi.com/products/30021/

Brand New out of the box. The Holley Ultra series uses billet aluminum metering blocks so I don't think that is the problem (Although there could be an internal crack in the main body). Also I put a different carb on it and it is still fouling the plugs. That is why I am thinking that this is a reversion problem. I would rather try to get this tuned than to chuck a brand new carburetor, but it may come to that if I cant get this tuned right.

Good to hear it is new carburetor!

 

[B229218]

It's my experience that open headers cause a lean condition. How long are you running it and at what RPM before you read the plugs?

I haven't gotten it out on the the road yet, I am trying to get it so that it won't foul the plugs at idle. The reason I am thinking it is a reversion problem is the cam has a 108 degree LSA so it has a lot of overlap. I might have to go out and run it hard to see if that cleans up the plugs. I know that high performance carbureted cars in the past would foul plugs at idle but once they were opened up the plugs would clean up and run hard.

aftermarket f. inject. systems are speed density, they do not like low vacuum signal, which is what 108 degree cams create. 

1. holley d.p. always are too rich, put in brass set svrews in i.f.r. to lean down.

2. get a 110-112  lobe center cam, 108 is really causing untunable situation. My cam is 110 hydra roller kaase kr2 cam, 521 motor and had similar problems with quick fuel 850.