Plugs still white!!!

[missilemud]

have you tried checking the carb at the base? alot of time a holley wears out if you have to big a return spring,try this , when its running work the shafts on the butterflys and listen for a whistle, had a simular problem, it tuen out to be the base plate was beat .

[Hotcrusader76]

His carb is brand new. Bottom line is...
After I looked over his build last night, after he sent me a spec sheet, I determined that his carb was too big. His motor just doesn't draw the necessary air to pull the fuel. He was installing huge jets, and still nothing. A band aid fix would be to shrink the high speed air bleeds, but then his low end would suck, as if it didn't already.
On top of it all he's running drop-leg boosters which have a better high speed response on fuel draw over Annulars, so he was fighting two battles here.
He's better off with a smaller carb for now, and when he upgrades to more HP then he can recalibrate that HP950 to work his motor.
Good luck Scott!
~Ty

[Blown 472]

Ok, not to start a flame war, but I am not buying the too big carb thang, I have a friend (believe it or not) who has a 340 mopar, flat tappet cam, 11 to 1 ish comp in a car that has a 950 hp on it, no bog, no flat spots, off idle stand on it and it flat huals ass right to 7 grand. So I am confused now.

[Blown 472]

One more thing, I was just taking a duke and pondering, maybe what you are seeing is two fold, first too hot a plug to get a read, secondly high speed miss, too big a jet and you are sucking the bowls dry, way to check for that if you are in tha boat and dialed into it and it lays down, pull tha throttle back let the fuel catch up and then dial back into it, if it comes on strong and lays down agian, no fuel in tha bowls, then agian I ate alot of paint chips as a kid so take it for what it is worth.

[DansBlown73Nordic]

I don't by the carb size thing. I have a good friend with a 283 SB and he runs a 780 cfm Holley. The car runs great. So this 950 should work on a Big Block.
Check the manifold bolts......

[Infomaniac]

Guys there is a lot more to consider than just the size of the engine and size of the carb.
I think the best way to describe "carb too big" is: Does the vacuum signal provided by the engine match the requirements of the carb.
A small engine can give a good enough vacuum signal to run a bigger than normal size carb depending on many differences in the design of the engine and also the combination "build" of the carb.
The reverse also applies. A big engine can give a very poor vacuum signal to the carb and require smaller than normal size carb.
My gut feeling in Ducky's case still is, it is running out of fuel. I had a boat in the past do the same thing. I would raise the float level 2 flats and it would run better. I did this three times and determined that the fuel system was just not providing enough volume.
[ January 03, 2003, 07:23 AM: Message edited by: Infomaniac ]

[Blown 472]

Hey info, since you live close to dorthy and toto, ever seen any twisters?

[Infomaniac]

I have only seen 1
No witches were killed

[Blown 472]

Infomaniac:
I have only seen 1
No witches were killed Up close?? or close enough to hear it? must be some serious stuff.

[DUCKY]

Am I not correct in saying that if I had insufficient fuel volume, then my pressure would also suffer? I have a gauge on it, and it never leaves 7-7.5psi. After a WOT run, I shut it down clean, and pull the bowl screws out, the bowls are full. And I have checked the intake and carb base for vacuum leaks with propane. Guys keep in mind too, I have the little tiny oval port heads. The intake ports are smaller than that of a 350!!!