Thread: Help, I am ready to give up!

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I have a 1969 Camaro I just built a BBC 468, I am struggling with a new carb, and its about to get the best of me. The motor is a 454 with forged flat-top pistons, and closed chamber 69 heads, 10.0/1 compression with a solid flat tappet cam, I have a 4150hp 600 holley on an edelbrock rpm air gap intake. According to my math I should be under carbed, but I am fighting a hopelessly over rich problem that has me at my ropes end! Anybody have any suggestions I would greatly appreciate it, Thanks Kelly

Just how "hopelessly overrich" are we talking here? Clouds of black smoke, or just really lousy gas mileage? Jetting too fat, or float not sealing?

fouling plugs, and clouds of black smoke, I have blocked off the secondary power valve, and almost bottomed the mixture screws to the lean side, and it has had no effect at all. I am really lost on this one, but hoping somebody can give me some ideas, thanks, K

What is the fuel pressure at the carb inlet?

A Little Over 10 Psi, It Bounces Between 10-15 Psi Eratically, Thats On My Line Guage At The Carb

i ALSO HAVE THE CARB JETTED DOWN TO FACTORY SPECS, F-70, R-70, WITH A 6.5 POWER VALVE IN THE PRIMARY METERING BLOCK AND A PLUG IN THE SECONDARY BLOCK. tHE FACTORY SPECS ON THIS CARB LIST NO P. VALVE IN THE SECONDARY BLOCK, DOES ANYBODY KNOW IF THE 600 HP HOLLEY CAME WITH A POWER VALVE IN THE SECONDARY BLOCK?

Originally Posted by colesscamaro

A Little Over 10 Psi, It Bounces Between 10-15 Psi Eratically, Thats On My Line Guage At The Carb

If you'll adjust that down to 5 lbs, your problems will go away.

tHE MOTOR HAS BEEN DOWN FOR A COUPLE OF YEARS, I JUST RECENTLY PUT NEW CYLINDER HEADS ON IT AND GOT IT BACK IN THE CAR, IT ONLY HAD 1000 MILES ON IT WHEN I HAD A PROBLEM WITH ONE OF THE HEADS. THE BOTTOM END WAS STORED ASSEMBLED, AND I MADE SURE TO LUBE THE CAM BEFORE WE REFIRED IT JUST A COUPLE OF WEEKS AGO. I HAVE HEARD THE STORIES OF HOW SUCCEPTIBLE BBC'S ARE TO WIPING OUT CAMS, AND I ALMOST WONDER IF THE CAM WENT FLAT ON ME, I AM REALLY HOPING THIS IS NOT THE CASE!

Forgive My Ignorance But How Would I Do That? I Am Running A High Volume Holley Mechanical Fuel Pump, Would My Only Option Be To Add An Inline Press. Reg. ?

Scroll down to page 118 here and see the 4304M fuel log. Mount it on the Holley and run a return line to the tank. Pressure adjusts right on the log.
http://www.malloryperformance.com/pd...m_Products.pdf

tHANKS FOR THE TIP! IF IT WORKS YOUR A LIFESAVER, I APPRECIATE YOUR HELP, K

Agree fuel pressure is too high... you want somewhere between 6-8psi max. Which holley pump are you running? Electric or mechanical? You'll want a pressure regulator... that said, I've had my holley run with over 11psi at times without overpowering the seats and going over rich.

Another possibility is a blown out power valve... they will dump gas like crazy

Agree you are under carbed so your motor can't breath over about 4500-5000rpm... you should have at least 750cfm for street application and probably 950cfm minimum for a race car.

-Chris

definitely check the power valve, and install the pressure regulator with return line. I have heard of some people using the vapor canister return line as a fuel return.

if the line pressure were too high and was in turn overpowering the seats wouldnt that be eveident when trying to set the float level? I have set the float level with the engine running and had no signs the seats were letting fuel by, ie, fuel coming out of the sight hole. I have never had trouble with pressure before, with a different holley carb, I just cant seem to get the thing to lean out it loads up at idle ferociously almost as soon as the engine is running

most likely blown power valve... sounds like needle is sealing despite your high pressure although this could turn into an intermittent problem when moving a lot of fuel and having the needle stick open... it can happen... best to run about 7 psi... replace your power valve and see if it gets any better.

BTW: very nice looking Camaro!

-Chris