Hello, My car appears to have a Holley Carb on it made for a Ford..the part number is 8207- (should be 1976 460, replacement carb) My question is why would someone put a Ford 460 carb on a 350?? now it ran ok on the vette..but I put it on my Pontiac 400 and it would not run at all no matter what..the primary jets are similar to any 1850 but everything else is really different..problem is since I changed over to a good Q-jet..the Vette won't run right..So IDK?..the car is currently apart so I won't have it running again for awhile..just wondering why it used that weird Carb??

 

The only explanation that I could think of is that a PO had a QJet on it that gummed up and quit working and he happened to have the Ford carb sitting around, put it on, and lo and behold it ran. After all, the carburetor didn't know it was on a Chevy...

 

The weird thing is that the carb was on a holley System Z manifold..and both have 1983 casting dates..I wonder if there is some special thing about that carb, matching the type of manifold??..maybe just a coincidence ..the motor had a bad popping problem that turned into a massive (not wanting to run at all) problem after my very good ( had it on at least 3 different motors 350-425 ci) Q-jet was put on it.

 

Does it use the reverse idle circuit, by any chance?


Scott

 

I don't remember.. I turned the screws both ways though to try and correct anything..but it still would not run (it would idle, just stall on tip in) on the pontiac..I put it on the pontiac because it was running good and I wanted to see if the vette's problem was the carb..It ran better on the Vette but still had a pop in the exhaust..the Q-jet (on the vette) would still pop from time to time..but after a while the Q-jet would not run on the Vette anymore without really Backfiring through the carb..where the holley would keep running.

 

Carburetor problems are very, very difficult to diagnose and fix over the internet, when dealing with someone who has very little knowledge of how a carburetor works. A lot of the time, you just won't even have the necessary vocabulary to understand the answers that are given. I am not trying to discourage you in any way, I'm just saying that the whole process will be much, much easier if you take a little crash course on how carbs work. Here is some recommended reading:

http://en.wikipedia.org/wiki/Carburetor

http://www.popularhotrodding.com/tec...k/viewall.html

http://www.bob2000.com/carb.htm

http://www.carcraft.com/techarticles...e/viewall.html

http://www.junkyardgenius.com/holley/tune01.html

http://v8tvshow.com/content/view/110/28/

http://www.nastyz28.com/~ericf/tech/htune.pdf

http://www.youtube.com/watch?v=6KjjN...eature=related

http://hotrodscott.blogspot.com/2007...ingtuning.html

Here's a good book about Holley carbs. Go down to your town library and ask if they have it. If they don't, they can get it from another library and let you borrow it for a few weeks. Read it from cover to cover.

http://compare.ebay.com/like/2203533...Types&var=sbar

Good luck!!


Scott

 

That's a very well informed suggestion, Scott. I have dinked with carbs for years, more than any other induction setup and I can learn something, to follow your lead. I hope the OP can see it for what it is.

Thanks!

 

Let's get one thing straight, here! I am definitely not a "carb expert" in any way!!!!! And I am not just being modest here. If somebody wrote a book called "What Scottyp99 Doesn't Know About Carburetors", it would probably be a very informative book about carburetors! LOL!

However, I can usually stumble along and get a carb running well, not because I am an expert on carbs, but because I did a little studying, and I know how carbs in general work. I mean the basic principles of how a carb works. And they all work the same way. Basically, it's all about differential pressures. They seem complicated and fussy, but once you know the basic principals of how they work, you will see that they are actually pretty simple devices. However, these basic principles can be a little tough to wrap your head around, at first. It is well worth the time and effort to learn the basic principles of how carbs work, though, even if it's just so that when you eventually do have a problem you can't figure out, you will be able to understand the answers you get from a real carb expert. Like I said before, I'm not a carb expert, but I do have the ability to have an intelligent conversation with one. And, I stayed at a Holiday Inn last night, so I got that goin' for me, which is nice.


Scott

 

I'd like to take a stab at the forward of that book...

Scottyp99 and I have the same carburetor, our paths have crossed on the forum and we have scoured the internet for enlightenment.

From Lars, I learned that "Most carb problems are really timing or ignition problems." That was a hard one. When I rebuilt my Qjet with the information from Lars, Cliff Ruggles and Doug Roe, I was tuning for performance. Lars advice to me was to use manifold vacuum for my advance and it worked like a charm.

Then, I bought a used Holley 4160 600 cfm to put on my 350. I couldn't get the carb to run right. Now I was tuning for problems. First, it backfired. Holley made that easy to fix. Then, it would hesitate under light acceleration. I spent a lot of time trying to adjust this out of the carb. Then, taking advice from yet another kind expert, I plugged the vacuum to the ported supply on the carb. That is all it needed to work perfectly. It was the last thing I could think about. However, it confirms another old saying which is "Tune to what the engine needs, NOT what you think it needs."

On a final note, a friend of mine has the same 600 cfm Holley on a Ford 429. Please don't tell my Vette that for fear it may protest.

 

thanks for the replies..I'm no carb pro, but I have rebuilt a few hOlley 4160s and I have the Doug Roe book on Q-jets and the Holley Book too. I've also fixed my Holley Hp when it wouldn't run right..but I just didn't know that much about Reverse Idle on Emissions Holley, or why someone would put the same carb on a 350 from a 460 but i guess it's vac secondary carb so it does not matter..also the balance tube thingy on the Z-series intake is kinda odd too..I understand it's function but I can see if it was gummed up it prob would cause weird problems..Oh I rebuilt the 8207 before I put it on the car..set the float levels right and even changed the PV to stock 8.5..still couldn't get it to idle on that Poncho..ran ok on the vette (sans the popping)

 

Sorry, man, my mistake, Didn't mean to imply that you are a dummy. If you have rebuilt a few Holleys, you should be in good shape. If you want to know if it's a reverse idle carb, unscrew one of the idle screws all the way out and look at it. The reverse idle carbs work by adjusting the amount of air that is let into the idle circuit, as opposed to the regular holley idle system, which regulates how much fuel is introduced into the idle system, with a fixed air bleed. So, you can see that it would have to work backwards (turning the screw in richens up the idle circuit by restricting the amount of air from the idle air bleed) Anyway, once you have the screw out, take a look at it. If it's reverse idle, it will be much sharper and pointier than a regular idle Holley (because you are metering air, which must be metered more precisely than fuel) You still start at 1 1/2 turns out and tune from there. Everything else should be no different from a standard Holley carb.


Scott

 

Hey no reason to apologize..I really appreciate the links..You can always learn something different..I'll have to take it apart again soon..I never really figured out why the vette was popping. I pulled the motor and got another, but then one thing led to another and another..and birdcage rot..and then everything had to come apart..but I feel I'm messing with a pretty unique car..so now I'm trying to figure out why it had certain mods done to the stock #s matching motor..the hood (motion type) has a burn on it where it looks like there may have been a supercharger of sorts..just trying to figure the car out before it all goes back to being a car again..Thanks

 

WOW I thought I knew something about carbs until I got thru reading the stuff ya'll spelled out!!! I guess I better quit messin with those screws on that carb or I'll never get that lawnmower runnin!!! Thanks fellows

 

what I do, is once I get the thing running halfway decent, write down all the settings. That way, if I get the thing all out of whack, I can just start over from a known good configuration.


Scott