carb suggestions for a 445 fe

[Tom Kirkham]

The best running carbs we have used are modified Holley 9381 (830 CFM, with annular boosters). We mill the air horns and restrict the PV circuit. We also tune up the accelerator circuit (cams and squirters). This carb is very drivable, but will be down about 10 HP on a dyno to an 850 DP. In light weight cars with big engines I prefer mechanical secondaries. The other good thing about this carb is it is one of the least expensive Holley carbs you can buy.

[wrench87]

that looks like an interesting carb, when you alter the power valve circuit are you removing the valve and plugging it? what about no choke do you have any cold start issues?, how much do the mods cost?. does this carb have the 2 rows of air bleeds on the metering block?.

[RICK LAKE]

wrench 87 Not to step on anyones toes but, KCR would be the best bet for matching a carb to this motor. You are using his camshaft, and heads. You didn't say what rpm the motor is going to run in. THIS is a big thing. If the car is going to be a street car with a little track time, a dual plane manifold works great to about 5,500 rpms. This is where the single plane starts to take over and makes more power in the top end. Torque makes the car move, HP is what helps it go at high speed. You didn't print what the LSA is, so I am going with a 110. Which ever manifold you use, Sent it out to Joe craine and let him do a port matching job on it. He equalizes all the ports to flow within about 5-7 cfm. This helps balance out the rich and lean cylinders in the motor. Do you have an RPM limit on this motor? With a hydro roller camshaft about 6,500 is a good safe limit. I am not a big fan of big carbs. If this was my motor, a 650 dual feed dual pump with 50cc accellerator pumps would be just fine for around town driving and a little playing. A 780 would be the biggest I would use. I believe you are looking for drivability and MPG of better than 7-10. Either will need some dyno time to get the A/F numbers correct. If you live in a cooler weather climate, I wouldn't remove the choke housing for cold startups. It does effect the air flow into the motor and cost power. The other thing is your exhaust system, who's pipes are you going to run? Back pressure is the biggest killer of cobra motors power. Running a real clean blow through system a 5-7 HP loss at top end, you do kill a little of the torque down bottom but this is a plus in most cases. It stops from blowing off the tires off idle. Some pipes cost about 20-30 hp in the upper rpm range. The trade off is noise and your hearing. Ear plugs are a plus either way in the left ear, unless you like that ringing sound after a drive. I have 2 sets of pipes, ones for the track and the orginials for the street. ERA makes both sets. Cops don't like the race pipes. I am done Rick L.

[Tom Kirkham]

Originally Posted by wrench87

that looks like an interesting carb, when you alter the power valve circuit are you removing the valve and plugging it? what about no choke do you have any cold start issues?, how much do the mods cost?. does this carb have the 2 rows of air bleeds on the metering block?.

Do not remove the power valves. We are just making the power valve restriction holes smaller. The two holes behind the power valves are really jets. The problem is they are too big. So we make them smaller.

Cold start issues. You will quickly learn how many times you have to pump the carb to get it to start. If the carb is adjusted properly it will be a little bit cold blooded until it warms up.

The mods are easy to do. You can do them yourself. But you will need to have a wide band O2 sensor to get the carb really dialed in.

Are you asking about the emulsion holes?

The advantage of the annular boosters is the carb will work at much lower engine speeds than down leg boosters. Hence the drivability of this carb can be made very good. In other words you can run a bigger carb with annular boosters than carbs with other boosters...

[csx wnab]

Originally Posted by Tom Kirkham

The best running carbs we have used are modified Holley 9381 (830 CFM, with annular boosters). We mill the air horns and restrict the PV circuit. We also tune up the accelerator circuit (cams and squirters). This carb is very drivable, but will be down about 10 HP on a dyno to an 850 DP. In light weight cars with big engines I prefer mechanical secondaries. The other good thing about this carb is it is one of the least expensive Holley carbs you can buy.

i'll have to agree with tom, i have been running this carb on a couple of different types of cars. first on my dragrace chevelle with 502/4sp combo. and now on my 427 cobra. just some re-tuning and what a great carb. instant throttle response and if you keep your foot out of it........desent milage too. i love those 9381s.