When I first started messing with the fan issue the one that was on the car went up in smoke....put direct current to it when trying to solve the not coming on issue...my fault. The fan that is on the car now is a used one that I had sitting here that just happened to match up to the holes through the radiator, figured I got off lucky with that fan, but obviously not. I have no issue spending the $$$ on a good fan, considering the heat issues we deal with here. One more question...I am having tuning issues and I am certain that it is with the carb. 4 barrel Holley off of the 84 Bronco, I believe it is a 650. Would I be better off with a new carb and if so what Holley would be best for a 351w, or should I rebuild and rejet the one I have on the car now. Seems to be running lean...stumbles and backfires at higher rpm's (4000-5500 range). I will pull the plugs tomorrow to verify....sorry, later today (just getting in from last night!) and make sure the car is running lean. It makes sense to me that the Bronco would be jetted for less fuel and lower rpm's.

AZford guy, Contact Patrick at ProSystems for a wonderful carb. He will custom build a Holley for your application, after he gathers lots of pertinent information. His price is reasonable, not much more than an HP Holley off the shelf, and his customer service is outstanding. AAA product and company!

For your cooling fan needs go back to this thread here on CC, (the Lincoln or Taurus fans) http://clubcobra.com/forums/showthre...647#post963647

These 2 speed fans are complete with a shroud and easy to mount not to mention they are like 60 bucks at a wrecking yard. They do KICK A$$ but you will need to install proper wiring because they pull 28 amps on high!!

Sounds like you might have a wiring issue that is under suppling amperage and burning up your earlier fans .??

I did some carb adjustments today...raised the levels in the float bowls, they were actually pretty low, and I put in larger jets. I have not had a chance to drive the car car yet, because the second fan did burn out while I was idling the car..... With the heating problems I have been having and two dead fans already, I am not sure if I want to trust a junkyard fan....so on Tuesday (I hate holiday weekends) I should be able to go to an auto parts store and buy a fan for a 90-95 V6 Taurus, 3.8....is that correct? The relay I have installed is a 50 amp....so what size wire should I use for the main power supply and to the fan? Should I use the same heavy gauge wire for the grounds and to the switch as well?

I doubt you would want to purchase the fan assembly from the dealer $$$$ and a parts store will sell just the replacement motor. Buy the junk yard version and buy a replacement motor if you have issues.

I ran 2 relays with diodes to control my Lincoln Mark 8 donor fan assem. The battery feed does need to be a AWG #10 in and out of the relays. A ground wire from the fan motor housing to a chassis ground should also be a #10 wire. Control or signal wiring
to /from relay and switch or sensors do not need to be that large because the handle a small amp load.

I suggest you use sensors to ground the relay-s and install a 3 way switch to select fan speed and manually turn the fans on. I use 2 different temp sensors to turn fan on low and then high if temp reaches second sensor. It is all ignition B+ enabled but also can over-ride the sensor trip points and turn the fan to low with a dash mounted switch.

Make sure you pick up battery B+ direct and not after it enters your main fuse block wiring . I use either the battery lug on the starter or from the battery lug on the alternator. Jeff C

I had a couple of Holley 4 barrels sitting here and I took them apart to look at the jets. They were all #61 jets, same as the carb currently on the car. The two carbs I took apart did not look like they had jets in the secondaries, which I thought there would be, just a flat plate bolted to another plate and gasket. The inner plate would not come off without major force, so I left it alone. Since I had an abundance of #61's, and it was a holiday weekend, I decided to drill a couple of them out (not recommended, I know), but it would give me an idea of the stumbling/backfire problem is from a lack of fuel. Took the car for a drive at night since it was cool enough not to need a fan and it actually ran a lot better!!! Ran very well under hard acceleration. A couple of questions for those with a bit more experience...when I am at a higher speed (mph) in a higher gear (4th or 5th) and very low throttle and RPM, say 1,200-1,400 there is still a noticeable miss and stumble. Not bad and not that often, every few seconds and just enough to notice if I am really paying attention....I know that the engine has high compression, don't ask how high, I don't know, but I cannot rotate the assemble by hand and I cannot push start the car (it just stops dead when the clutch is dropped) and I do not know if the engine has any cam at all....it is not radical, but when idling it does have a decent lope. Could this, slight stumble and miss at low throttle, be normal for this engine? Or should I continue to trouble shoot the ignition system? It is starting to run very well WOT, but we all know these cars cannot be driven that way regularly!!!!

The plate you are talking about, was meant to replace the metering block and jets in the secondary system on a 4160 carb, the holes were a predetermined size. You can buy a new secondary metering block to replace the plate as well as longer screws and transfer tube needed if you add new metering block. It's been a while since I have played with one of these plates and I don't think drilling it out and installing a jet is a great idea. New plates with different hole (jet) sizes are available for tuning.

It could be that your miss or stumble at low speed when you floor it is actually "bogging". Or maybe your accelerator pump is not working properly. Ignition timing might be off too. You can an adjustable style vacuum actuator (for the secondaries) and adjust the secondaries so they open slower (or faster).

The Holley carburetor website has a lot of helpfull information.

Also the #61 jets sound a little small.

A 650 cfm carb should be a good size for a mild 351. I wouldn't go to a 750 unless you have the cam and heads to go with it.

Remember the 3456 rule. Multiply the engine volume in cubic inches times the maximum RPM you will be operating at, then divide the product by 3456. THat should provide the proper CFM flow for your carb.

The weight of the car, cam and other things enter into this too. Holley acutually has a handy calculator on their website for selecting the "right" carburetor size and type. :3DSMILE:

I have not checked the secondaries on the carb that is on the car, so I am not sure if it has jets or a metering plate, just started with the primaries to get the car running better. Drilling out the #61 jets had a major improvement already (drilled them out just enough to see a visual size difference, nothing drastic). My question still is...if an engine is set up with higher compression and a bit of a cam, is a bit of a stumble/miss while at low throttle while driving normal? Timing is at around 30 BTDC which is where it seems to run the best. All plugs are good and firing, vacuum advance on the dist. is working, my only thought now, if this is a problem, is that there may be an intermittent issue with the coil......Again, the car seems to be running much better now, but the slight stumble does seem right to me.

I did not mess with the secondaries on the car....I only drilled out the jets on the primary. The car is not bogging when I floor it....it just has a slight stumble while cruising at a lower RPM. When I stomp on the throttle, the car takes off and runs strong.

Hey AZford,
How about a side bet for 5 bucks, payable on the next run we see each other? I bet your stumble is a timing issue. I bet your initial timing is too low and increasing initial timing to about 12 to 16 degrees will make the stumble go away.

If the initial is in the 6 to 8 range now then increase to 12 degrees .... increase a little at a time up to a max of 16* if she will take it without pre-ignition or pinging. If the new timing takes the stumble away then you need leave it there but then check the total timing. You may have to restrict the mechanical so total is more like 34* to 36* total timing with the initial bumped up to 14ish.

Check you initial timing as it is set up now ..After you take the bet for a fin of course and let me know the outcome. Jeff C

Does it stumble right off of idle? How do you have your idle set? All on the primary side? Or do you have a little bit of the secondaries opened up too?

That bet would be a bargain at twice the $, unfortunately the timing is already at 30 BTDC....this`is where the car runs the best....from what I understand the ignition needs to be advanced until it starts to "ping" then back it off.....with as loud as these cars are how in the world can you tell if it is pinging???

The carb only has idle adjustment screws on the primary side. Secondary throttle plate is closed 100% at idle. Took the primary screws in all the way, backed each one out 1/2 turn and hooked up a vacuum gauge. Increased the idle screws until I achieved maximum vacuum, then backed each one in a hair to drop it 1 hg of vacuum....kinda tough because the vacuum is not steady....the needled bounces and fluctuates around 1-2 hg, but is strong around 21 hg. The car idles fine...just a bit of a lope to it. There does not seem to be any miss at idle....only when cruising with minimum throttle, if I down shift and kick the RMP's up the stumble/miss goes away.

Here is how I have the new fan wired up.....do you see any issues? It is a 50 amp 5 pin relay, but from what I understand in a simple on/off set up the 87A (center) pin is not used.
http://i158.photobucket.com/albums/t...lf68/relay.jpg

What kind of carb is it? You may be into the transition circuit on the primary side, which will cause a stumble when you're in between the idle circuit and the jets.

As for timing, you need to choose a little more "scientific" way of waiting until it pings then backing it off.

I'd set the initial anywhere from 12-16 degrees and check the curve at full advance. 34-36 degrees total should be fine. Check to see where the total advance comes in. Lighter cars will stand a quicker timing curve. I like my Cobra engines to hit total advance around 2200-2400 rpm.

My suspect is sticky float. What carb do you have? 600 or 650 Holley?
Drop the car off to Oklahoma with me for a month and I'll let you know if it was just an Az thing!

I'm not one to ask for advise and then not follow it....and since it was easy and free I backed the timing down to 16-18 BTDC.....although it pains me to say the Chevy guy is right......well, the Chevy guy was right. Problem seems to be gone, took the car out for a run into town to get groceries once it quit raining and I did not notice any stumble or miss at all. If you Phoenix guys ever manage to get a run or gathering together that I can attend, I owe you $5 Jeff. I still would like to do some tuning or changes to the car, I am still not hitting my "power band" until I get up around 5,500-6,000 RPM, which would be fine if I was driving around at 150 mph all the time, just not much punch at low RPM daily driving. At least the car is running better now, and for the time being, it is running. 1st trip so far with the new fan wired up and it hasn't burned out yet.....keep your fingers crossed for me! Thanks for all of the continued help. Mark

The carb is a Holley 600 I believe, #80457-1, took it off of my 84 Bronco that has a 351w as well. If you read this entire mess of a post, the carb that was on the car, a Motorcraft by Holley #50264 would vapor lock after 10-15 minutes of driving in the heat. Putting the Bronco carb on the car solved that problem. I will have to pick up some jets in the next few days, since I am sure that the home drilled jets will not be ideal. Between the larger jets and the timing I think I may be in good shape. I still may want to put a better carb on the car....not sure if a Holley that was on a full size Bronco is the best application for a car like a Cobra....what do you think Brent?