Rebuilt 67 289/302 installed in 65 F100. Rebuilt 1850 Holley 4bbl. 600 cfm, secondary vac., manual choke about 4yrs ago. Truck running great until replacing all components for tune-up about month ago. Yesterday went back and rechecked all gaps, timing, etc., and no improvement. Symtoms point to carburetion. Considering replacing rather than rebuild an antiquated carburetor. My question, whether to rebuild on go with replacement, if so, any suggestions on brand, model; also, any opinion if the 600 cfm is bit much. Thank you!!

 

The Holley 0-8007 vacuum secondary is a 390 cfm carburator with the same replaceable parts as the 600 cfm, so you can buy them off the wall at the auto supply. The advantage of this modern carb is that you can replace the jets to tune the carb for whatever flavor of reformulated gasoline they sell in your area. In my area I find the imitation gasoline runs way too rich in historic carbs, it fouls the plugs and is hard to start on a 1950's or 1960's carburator. I run the smallest jets in my holley on my 255 cfm small block v8. The disadvantage of this carburator is that the design prohibits more than one accelerator pump a minute, so you can't start the engine by pumping 3 times in the cold like I used to on my fomoco carbs. You have to set the choke precisely to start the engine cold. You then have to hook up the electric choke heater to get the choke off. I've installed a 76 ford truck accessory relay to unload all the modern electric junk off the ignition contact of the key switch, keeps from burning up the switch with too much current. I got a 62 fairlane cheap because the owner was running the electronic ignition off the ignition switch, it kept burning the terminal off the wire harness. Hook up the load sides of the relay with 10 ga wire and a 30 amp fuse, the ignition switch runs the relay coil.

 

Indianajo, appreciate the info, thought I would pull the Holley and see if anything obvious, not sure if I want to rebuild again; although, it's been a good carb over the years. If not, then likely go with a new Holley, appears there a few more options with CFM on the electric choke variety, thanks for the info on how to hook it up.

 

I agree that if you do buy a replacement carb it would be a good idea to get a smaller one.
Keep in mind that the High Performance 289, designed as a high rpm engine, only had a 480 cfm carb. That engine was rated at 271hp at 6000rpm.

Indianajo;
"The disadvantage of this carburator is that the design prohibits more than one accelerator pump a minute, so you can't start the engine by pumping 3 times in the cold like I used to on my fomoco carbs."

This is quite strange. I've never heard of this problem with large or small Holleys. Perhaps the accelerator pump diaphragm is age hardened and takes a while to relax back into its original shape.

 

The only problem with replacing with new is that you're going to get a smog carb.The one you have ,I assume,is not.More horsepower is attainable with the latter.I also have a 600 cfm holley,vacuum secondaries on my 289,there's no problem with this much carburetion on my engine.

 

Not sure, thought only difference between smog and non-smog carb is a 1/4" pipe thread plug. That being said, called few auto parts stores and finally found counter person who sounded knowledgeable about carburetors. Took the ole carb figuring if decide on a replacement I would have it to exchange. The counter person I spoke to on the tele took a few minutes to examine the 1850 and then started describing features the replacement carburetor does not include then basically gave me the 'don't build them like they use to' pitch and ended up convincing me to rebuild it. Anyhow, tomorrow intend to disassemble and soak in carb cleaner for a few hours, somewhat impatient, so will try and maintain a relatively low caffeine level before taking on the reassembly. Can't wait to get the show on the road, the truck that is, hopefully the rebuild will solve the problem!! Again, appreciate the suggestions, and info!!

 

Take your time on the rebuild. If you don't clean it properly you are wasting time and money. As far as the electric choke, Holley makes a kit to convert it if you want. The Holley 1850 is a vacuum secondary square bore 600 cfm carb. It is still made and sold today, but with more plastic parts. The only real difference is that they know come with power valve blow-out protection which you can add as a kit that includes the check valve and drill bit for less than $10 from Summit or Jegs. Don't buy a cheap rebuild kit, I highly recommend a Holley rebuild kit, better parts. As far as a smaller carb you would probably never need all 600 cfm ( only you know how your motor is built and how it is run) but that is the good thing about the vacuum secondary carb, it only allows what it needs for air and you can adjust the it by the springs in the secondary diaphram.

My take is keep it, rebuild it right and spend the time to dial it in, no carb is an out off the box and work great on everything carb.

 

Dave just saw you live in the Santa Cruz mountains, I lived in Felton for a little while and alot in the Campbell/Los Gatos area.

 

Dave, yes San Lorenzo Valley resident, girl friend and I love to take nature walks thru Henry Cowell Park. We live north of Boulder Creek, think I would give it up for little part of Gods country there in Truckee, being within short distance to Reno is an added bonus.

I did go for the Holley rebuild kit, cost almost twice that of the generic but I used the Holley kit the last time and found the instruction sheet very helpful and the rebuild went fairly easy. Certain the 'power valve check ball' kit is not included. Went online to the Holley Carburetor spec sheet and the kit did not list the 1850 in the application, will call them in the morning. Would not be surprised to find the power valve is the problem. Thanks again for the help.

 

I'm not saying the power valve is the problem. Just saying that if you are rebuilding it, this is the time to upgrade it by adding powe valve(PV) protection while it is apart. It is cheap protection for the PV in the event of a backfire.

 

Just that it would not surprise me to find power valve to be a contributing factor, appreciate the heads-up with the upgrade. Spoke with Holley Tech representative and confirmed the 4160 power valve check ball kit is the same for the 1850. Also, have to take back the rebuild kit, tole by Holley rep the correct kit for 1850 is Hly # 37-119.

 

PM received from indianajo:


The disadvantage of this carburator is that the design prohibits more than one accelerator pump a minute, so you can't start the engine by pumping 3 times in the cold like I used to on my fomoco carbs."

This is quite strange. I've never heard of this problem with large or small Holleys. Perhaps the accelerator pump diaphragm is age hardened and takes a while to relax back into its original shape.
Reply With Quote
Only if Holley is shipping defective parts on their new carbs. Do you own a 0-8007? You think I would have done all that wiring work if I could have got the car to start below 70 deg F without the choke some other way? You can see the accel pump lever come back up as it fills, takes over 5 seconds. Accel pumps fill through a hole, not with the diapragm, the holeinthe 0-8007 is probably about 100 times smaller than the one in the rochester fomoco 2bbl.

I'm not sure why this response was not posted but sent by PM instead, anyhow here it is. But in the future, let's remember to keep the responses in the regular forums, no need to use the PM for this.

In answer to the questions, no, I don't own a 0-8007.
As for the next question, well I can't possibly know why someone I don't know does or does not do something.

 

Having problems with gas leaking at the mateing surface of the throttle body to carb body. Floods when parked, which can be seen seeping gas in the secondarys with air filter removed. Was going to machine the carb body to make a better fit. but what would make gas travel from the metering block to this part of the carb when not running? Have a 3/4 inch phenolic spacer on so don't think the gas is boiling. Any ideas?

 

I would guess that the float level is too high or that the needle and seat are not sealing properly. Both will cause the fuel level to be too high, resulting in fuel draining through the idle circuits into the venturi near the throttle plates.

 

When it comes to trouble shooting carbs it's anyone's guess. Just rebuilt Holley 1850 and about to reassemble an extra I ended up with. I agree with Beanscoot. May want to start by getting the truck on level ground and remove the site plugs, if gasoline starts pouring out it's an indication the level is too high. Oh, have a small container on hand just in case to catch the overflow. If it comes down to where you have to remove the carb then I would include checking the secondary throttle plate adjustment, tighten set screw until it just touches the stop and then turn an additional 1/4 to 1/2". I use Pam, yes the cooking stuff, or 'tru flow' which is simular to WD4, and spray on a small brush and apply to parameter of the gasket so it does not get damaged if I have to remove later. If u have manual choke make sure the small round paper plug was installed when reassembled, not sure if it would cause the problem you are experiencing, it just took me awhile to figure out where it belonged. Anyhow, would be interested on how it goes.