carb suggestions for a 445 fe

[wrench87]

well i decided to run a carb set up instead of the mass flo fuel inj on my 445fe
i purchased a performer rpm intake a msd 8594 distributor, msd 6al box, i need to decide on a carb i wanted to see what people would reccomend.
also what is better on the street mech or vacuum secondaries?.
i am running one of kc's hydraulic roller cams .598-617 lift, 230-238 duration
i am using the diamond pistons with slight dish and stage 1 kc edelbrock heads.

[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?.

[Barry_R]

I do a lot of them with a basic downleg booster 750 double pumper. Tom is spot on with the peak power comment - we see about 10HP more with the bigger carb, but teh smaller stuff is better from a driving and transient perspective. I have not run the 830 annular, but it should be very good, and will give one a try soon.

Cheap vacuum secondary 750 carbs with straight leg boosters are down at least 20HP compared to the good ones...

[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.

[vector1]

rick, is that joe craine dr. j?

[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...

[wrench87]

rick the cam has a 112 lobe seperation i originally was going to run mass flo fuel inj i have all the parts but decided to go with a carb. it is just a street motor using the 4into4 headers with ffr sidepipes . we have a performer rpm intake on our prostock circle track car that was pulling 7300 rpm at thompson speedway last month so i think that 5500 is a little off?.
tom i have read that the annular boosters are to be run on a singal plane intake is this true, i have the performer rpm intake # 7105. it looks like kc runs the quick fuel 750,carb with vacuum secondaries and electric choke.
i would like th run mechanical secondaries up in the air about the choke.
our late model runs a zz4 with the holley 650 no choke starts fine in the cold like tom said it takes a few pumps of fuel to fire it cold?.

[Tom Kirkham]

Originally Posted by wrench87

...i have read that the annular boosters are to be run on a singal plane intake is this true, i have the performer rpm intake # 7105. it looks like kc runs the quick fuel 750,carb with vacuum secondaries and electric choke.
i would like th run mechanical secondaries up in the air about the choke.
our late model runs a zz4 with the holley 650 no choke starts fine in the cold like tom said it takes a few pumps of fuel to fire it cold?.

I have used these carbs on several of Keith's engines with Performer RPM intakes. They have worked great. The reason annular booster work well on a single plane intakes is annular booster is more sensitive to the weak signal to the carb found in single plane intakes. That is why you can run a larger annular booster carb than conventional wisdom would dictate.

The problem with the air horn (and the choke) is that the original style air cleaners are so short that the air horn interfere with the airflow.

[wrench87]

tom would thiscarb be to large for the 445?, i am sure you are using it on the 482?, also does it have any vacuum ports? i only need one for a pvc valve.

[RICK LAKE]

vector1 Joe Craine is in San Antonio, Texas # 210-521-4620 call between 12-4:00 pm Texas time. His work is like jewelery. Couple of the guys in the northeast here have had there manifolds done and you hate to put them on the car. As far as a power thing, He balances out the ports to all cylinders and gives you a cfm report when done. Takes about a week depending on how much he has to do. This is hand done with no or little CNC work. I run FI systems and my manifold doesnot need the same work as a wet one. Give him a call. I have the cell but would n't give it out on a thread to the public. Rick L.

[RICK LAKE]

wrench87 You are running 7,300 rpm with a stock performer RPM, on what motor? This manifold out of the box was tested, and the power band for it is lower at max then what edelbrocks shows. I would like to see the dyno runs with this setup and some of the specs on the motor. It is possible to turn a motor to 7,500 rpms with this manifold, YES been there done and seen it. power drop off was huge. This is way single planes where made for this kind of rpm range. I have Dyno 2000 and another software motor building CD. Both come within 3-4% of real numbers. Last 3 motors built where done this way and on the motor dyno and chassis they all ended up about 5ft of torque and 7-8 hp off. Sound like a nice magic motor you have.
Back to you motor, I think you will find that the camshaft you have is got a max of 6,400 rpm for the HP band. I also have one of KCR special cams that is a little bigger and it tops out at 6,700 rpms, .622" lift. Hydro lifters are heavy. They pumpup at high rpms. Strong springs will help control bot if you have them adjusted like both directions say the valves will not be closing and the motor falls on it's nose. Again been there and have dyno sheets showing this problem at 5,800 rpms with a 587-607" crane hydro roller. I am also running beehive springs. With turning 6,200 rpms and the lifters being pumped up, my motor runs like a solid lifter one but without the major power lose. .015" plunger depth when adjusting the rockers. Even with stromger springs about 6,500 rpms your motor will hit the wall too. Solids are the way to go for higher rpms with more power. I don't build HP motors, only torque ones.
You have nothing to loose with starting with the 650 DP. Thrown the motor on a dyno and see what the numbers are. Play with the camshaft timing. If the numbers on the dyno are not what you want, go to a bigger carb. Remember that dyno testing and street testing are not the same, and bigger is not always better. You are also not running a huge cam in this motor. You are running a 445 motor switch is 20 cubes more than a stock FE. My 482 eats up the 587-607" without any problem. Little lope and 14hg if vacuum at idle of 750 rpm. steady. You might want to search on the FE forum for some more info. Rick L.

[wrench87]

rick that was on a 358 chevy 12to 1 engine with a solid cam and a 1500.00 4412 holley 500 2 barrel carb, we have to run that intake track rule .
i dont want to go overboard on the carb but i only want to buy one carb so i want to get it right the first time. i like the forums so i can learn from others experiences and take it all in to help me decide. rick what would you estimate this engine will put out for hp and tourque?.

[RICK LAKE]

wrench87 You left out the magic words, solids, SBC, and 500cfm 2-barrel,which heads are the only thing missing. You could run that 500cfm on your motor and make good power to. Rick L. Ps there is a formula that gives you an all around number for carb cfm. 90% of the time this works pretty well. The biggest carbs I have ever run are twin 650 DP holleys, biggest single is a 780 with an 830 or 850 base. Anything more was a waste, burnt more gas and had less responce to driving or racing. Did we win many races NO but spent alot less timing screwing around with the carb, and working on the suspension and handling. IMO it's still about torque and getting all of it to the tires and ground and have it hook and haul. I am building a 498 motor with 4.375 crank, 6.7 rods, and 4.280 bore. 3 of the fastest running cobras are running under square motors. More stroke, less bore. Less rpms needed too. Sounds like longer life of the motor. Rick L.

[wrench87]

rick the chevy engine is running the older steel 2.02 bow tie heads. what do you think my 445 will put out for hp and tourque? i was hoping for 500hp but i know i went mild on the cam and the stage 1 heads have the smaller exaust valves, i just could not afford the extra at the time for the stage II heads so i dont know if i will hit my goal?.

[RICK LAKE]

wrench87 Without having all the numbers,crank #'s, 475-485 in HP and about 530-540ft in torque, depending on camshaft and where it's degreed. You will have a strong midrange from 2,600- 4,800 rpms I retard all my motors for torque. You will have to check with KCR and comp, I think they have an 4 degree advance built into the camshaft. Check this out when you assembly the motor. I my have this backwards. too early in the morning. Rick I think you will be happy with this motor to start. After some time the power BUG will bite and here comes the 600/600 club or higher. Biggest problem is too much torque in the bottom of the rpm level and blowing off the tires in 2 gears. Have to roll on the gas pedal and not punch it. Right now I have in the 500/ 600 HP/ torque club and need to adjust cam timing to kill the bottom end a little. Numbers are at the crank. 18% through the drive train drop. It's still a hand full. Rick

[Barry_R]

most of the 445s I dyno come in right between 475 and 500HP. Almost all are right at the 500TQ range. The RPM intake is a good one and with port matching will go higher - but the hyd roller is going to hold you to around 6200 or so peak anyways.

[wrench87]

i e mailed kc he suggested a 780 vacuum secondary quick fuel carb? or a 750 double pumper. whats wrong with running a mech secondary carb? its a light car i have 3.73 gears i guess the most important thing is driveability, i guess i want the best of both worlds still leading towards a carb with out a choke or choke horn and possibly annular boosters?.

[Tom Kirkham]

Originally Posted by wrench87

... or a 750 double pumper. whats wrong with running a mech secondary carb? its a light car i have 3.73 gears i guess the most important thing is driveability, i guess i want the best of both worlds still leading towards a carb with out a choke or choke horn and possibly annular boosters?.

A double pumper is a mechanical secondary carb.

Forum discussion on Annular booster carbs: http://www.fordmuscle.com/forums/all...ter-carbs.html

Here is a 750 Annular booster carb.
http://www.jegs.com/i/Holley/510/0-9379/10002/-1

[Keithc8]

What we battle all of the time is what the customer wants with carburetion. So many people drive fuel injection cars now because that is what everything has is that they do not understand carburetion and want it to work like fuel injection and it will not.
We have to use some of the electric choke carbs to try and make these customers happy with the starting of the car. I prefer a double pumper on most of these engines i most cases. Some of use know how to start a car with carburetion and a lot do not.
Tom has spent some time working out the 830 to work well on the engines we have done for them. The annular booster carbs work better on the bigger cam engines because like Tom says they do not have as much vacuum to pull on the boosters to work at low rpms. I have a customer right now that needs the electric choke but wants the car to run better below 2000rpms and this is where the annular booster carb will work better.

Good luck, Keith