Ignition Timing
On a side note, I haven't seen any posts from Mustangmike in quite some time.  Is he still active here?
Yeah he was on here yesterday about 5:00pm. I guess he just didn't have anything to say. LOL.


I am still here but have been busy trying to get the Fairlane project wrapped up.  It seems like the closer you get to the finish line the further away it gets!   Anyway, glad to hear you figured out the timing and picked up a new carb.  Did you buy the whole carb or just the main body?  I am trying to figure out what the HP stands for in that line of Holley carbs.  I am assuming it doesn't mean high performance.  

I only replaced the center section (main body).  I can't afford a new complete Holley carb.  The days of simply purchasing a new carb are far behind me.  One like the 650 HP shown below runs $650-$700.  Most all Holley 4 barrel carbs start at $500 these days.  Their cheaper models like the 600 CFM vacuum secondary, list number 1850, are not worth using.  For the past 10 years or so I have been purchasing parts to modify or assemble a carb.  A few used parts from Ebay, but mostly new parts from BLP performance and AED performance.  After a while so many parts are accumulated the cost isn't too bad to assemble another carb.

In the last year or so Holley has made available most all of their popular main bodies complete with boosters, air bleeds, etc installed.  I also installed new metering blocks from AED performance.  Of course, I installed the original size idle and main jets that match the main body.

Below is a Holley 650 CFM HP style carburetor.  The HP series have no choke horn and are contoured differently to improve air flow into the carb.  They also have screw in air bleeds which helps tuning.  I've used one once in the past when only the 750 cfm version was available.  750 was too large for my motor which is why I opted for the 650 version.  The HP type main bodies have a noticeable improvement in performance.  No choke horn, but the idle circuits are usually fairly rich so it doesn't take much pedaling for the first couple of minutes when cold.

[Image: 0-80541-1.jpg]
Sweet...so does this carb resemble the one you are using on your car now?   I have been using Edelbrock carbs because someone once  told me they are simple and not as finicky as the Holley carbs.   But now you got my mind thinking!
I'd still stick with the Edelbrock. For the simple set it, and forget it. The later Holleys are much better then they used to be, especially since the gaskets don't shrink, like the old cork ones did. But they're still not as spot on, and reliable as the Edelbrock / Carter carbs

(08-22-2018, 09:10 AM)Mustangmike Wrote: Sweet...so does this carb resemble the one you are using on your car now?   I have been using Edelbrock carbs because someone once  told me they are simple and not as finicky as the Holley carbs.   But now you got my mind thinking!

Yes mine is the same except for the AED performance metering blocks.  These are less expensive the stock Holley metering blocks specific for that main body and they have screw in replaceable idle feed restrictors (believe or not, made here in the USA).  QFT also offers these billet metering blocks.  The QFT metering blocks are made in China, the quality isn't very good, and for some reason they are thicker than Holley metering blocks which creates some problems with getting the accelerator pump(s) adjusted and reinstalling the fuel lines if you use hard steel fuel lines.  I have two pairs of QFT metering blocks sitting on a shelf.  They just never seemed to work as good as stock Holley or the AED metering blocks.

Holley also has Street HP carbs that are better suited for a street driven car.  If I were to get a new complete HP style carb I would have went that route.

Like JTS mentioned the Edelbrock carbs are better suited if you don't want to tinker with the carb much.  For me, I enjoy tinkering with carbs so Holley carbs don't bother me.  They don't leak like the older models and the castings are better.  Motors tend to make more power with a Holley as opposed to Edelbrock carbs.  If you select the right size, not much additional tuning is needed.  There are a few big mistakes many people make with Holley carbs.  (1) Carb selected is too large or too small.  (2)  This is a big one, the primary throttle plates need to be in a particular position at idle.  Out of that range and things don't work right, i.e. too rich, off idle stumbles, etc.  To obtain that position you often need to also adjust the secondary throttle plates position at idle.  (3) Not knowing how too tune the accelerator pump circuit.

[Image: 6580-rd.jpg]
I see more often than not people running carbs way too big for their application.  I have never ran anything larger than a 600 cfm carb on my small blocks and they never seemed to be choking for fuel.  Right now I am not ruling out replacing my Edelbrock with a Holley carb but the Edelbrock seems to be running good. Although I need to adjust the electric choke for cold starts.

Mike, When you get a chance post a picture of your car again.  I think forgot what it looked like.

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