It appears that the housings are new cast, or machined with media blasting to give OEM appearance. I am going to contact them.

What I want to know is if they can upgrade a numbers correct DIST for a dedicated appearnce/restoration.

"Chinese knock offs ... WHY? would you even consider using a low quality, poor performing with No  tech help or parts available distributor in your classic early Y-Block Ford?  When you start installing those low grade Chinese parts you might as well just bolt in a 350 scruby/350 trans and a 3.50 gear and build a belly button car. Do you really want that Chinese distributor with scruby cap starring at you every time you open your hood.... call me a purist but it would be way to embarrassing for me. We will not work on the Chinese Import fake distributors, no repairs, no set-up or curving and we have no parts for them. In this industry the last guy to work on it is responsible for it... we will not take responsibility for tech information or be a  warranty dump for Imported low quality products."

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Three years ago, we installed an electronic distributor from CRT Performance who are on ebay.
Works great with a 600 cfm  dual feed Summit carb.

FORD Y-BLOCK 239-256-272-292-312 Small HEI DISTRIBUTOR BLUE + PLUG WIRES USA

Any new carb cannot be expected to work on every application, unless it is a DIRECT OEM or QUALITY REBUILD for the exact application.

It can have accelerator pump mis-adjustement, cam selection (duration of shot), squirter size(s) as mentioned or in very special cases may need a 50cc accelerator pump. It has to be tuned for the application.

As for using manifold vacuum for the DIST ADV, this will bring in full vacuum advance @ idle and tip-in. No gradual application of vacuum advance.

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When I started using a 390, which I really like now, I had to change main jets too. But still had an off idle hesitation/bog. I finally cured that by going to a larger squirter, the one that comes with the carb is really small like .025 and I changed to a .032

Well, 7 steps is close to 10. That would be my starting point. With the changes in fuel, etc. you’re probably right on the money.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

When these 390's are shipped new they seem to have 51 main Jets. Probably because they can be used on everything from 4 Cylinders up to small V-8's. They are all supposed to be wet Tested at Holley. The last new One I bought in the Spring had a definite  Fuel Smell so I assume it was tested. It only had 51 Main Jets. 58's seem to work well for my Stock Engine. Anyway He has had some Suggestions given. Look at the Basics first..

  

I went back and reread the whole post. The only time I had a Holley with a BIG bog, just short of not driveable, it was the main jets. The carb had been shipped (it was a new 4160 vacumn secondary) with the mains 10 sizes small. Like 55 instead of 65. Hard to remember, that was 1968. Problem solved. So maybe worth pulling the bowls and checking the jets. Doesn’t seem QA has improved lately.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Maybe the main Shaft? The Housing they sell is for sure New.They were offering them on Ebay for awhile with only a $25,00 Core charge. The fact that He can't even really drive it is not something I have had a problem with having done 3 of these Swaps. Upsize the Jets to 58. Set the Timing at around 8-10 initially and they can at least be road tested and run well  and then I would fine Tune them.He has had 2 Carbs on this and still no Improvement. I am very interested to know the final Outcome when He figures out what the Problem is.

  

Not to hijack the thread, but there’s a core charge on the FBO distributor, so there’s something they’re reusing. If their name had come up a week earlier, I’d had stopped in and seen them. I was driving thru Cottage Grove, OR.

On the carb side, you might go back and look at some earlier post on setting the secondaries on Holley carbs. I don’t know if it applies to the 390, but it might if it’s a 4160 series. I think it was a post by Greenbird56.



miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

I was just looking at FBO Website. Looks like a Quality Product made in USA.If You check some of the Items that were suggested and still no Improvement maybe U should check with FBO and see if they have any suggestions regarding their Distributor. If You were not having Problems before changing Carb and Distributor its One or the Other which is causing the Problem and I think its Ignition related not Carb. Let us know what You find when doing some checks as suggested. Did You check the Jet Sizes? They need to be around 58. New 390 Holley Carbs come with #51 from the Factory.