'66 Mustang leaky carb

[HerStang]

After performing many searches of the forums for my specific issue I didn't find an answer, so I will apologize now because I am certain I am not the only one who has run across this issue.
Backstory - bought my wife a 1966 Mustang with the inline6 200cid for her 40th birthday. Had if fully restored including paint, full interior, wheels, brakes, engine, added radio, a/c, etc. When having the engine rebored they cracked the block, bummer. So a new crate engine was installed (note-she refused to let me upgrade to a 289 or 302 citing the work needed to replace suspension etc.). She then informed me she didn't like the 3 speed because the clutch travel was too far for her. She's barely 5' so I get it. So, I swapped the transmission to an automatic (because she wouldn't let me sell the damn thing and buy one with an auto already in it because it was her birthday present)

fast forward to now.

The new engine has about 700 miles on it and it sat for a couple of months without being driven. When I jumped in it to spin it around the block the carb began leaking HUGE amounts of fuel from the bowl. After opening the carb I found the plastic float had a crack and was full of fuel. After much searching I found a brass float and installed it. That didn't resolve the issue so I bought the Walker rebuild kit assuming there was an issue with the needle. The kit has a needle with a rubber seat where the henkyo does not have the rubber seat. This did not resolve the issue either. So now I am out of ideas and turning to strangers in a forum setting who are likely much more knowledgeable that I am to hopefully help me resolve the leak and get the car back on the road.
My other option is to bite the bullet and spend the $800 for the rebuilt autolite OR install an EFI system.

So my questions are -

Do any of you have an answer to the leaky henkyo carb?

Have any of you replaced a henkyo with a rebuilt autolite and what was the outcome?

Have any of you swapped from carbureted to EFI?

Thanks for any and all suggestions, advice and help!

 

[62falcon wagon]

Float adjustment? Too much fuel pressure? Both?

 

[Adriatic Machine]

Make sure the needle and seat are a matched set / style. If the needle you installed is different from the old one then the seat is likely different as well.

Here are a few styles that I found in my Holley 1904s. Each kit came with a needle and a compatible seat.
Good luck!

 

[Frank]

Welcome- you may have excessive fuel pressure from the mechanical pump, this is a recurring issue with newer replacement pumps.
Also be sure your fuel filtering system is sufficient. This is resolvable, replacing the carb is not the immediate answer.
1)verify correct size needle/seat, set correctly
2)verify clean fuel
3)verify fuel pressure.

Yes the Holley sniper 1 barrel works well and seems to have few issues. It's a lot of fabricating though, the fuel system converted to high pressure.

 

[HerStang]

Thanks for all the info and suggestions, y'all.

@62falcon wagon I'm certain the float position is correct, but you and others have mentioned fuel pressure so that is on my list to check out.

@Adriatic Machine It could be a needle/seat issue as I literally just dropped the walker needle in (it looked identical).

@Frank I have dual filters, one in front of the fuel pump and one in front of the carb so I don't think that's the issue. I am going to check the needle/seat to verify.

Will post again with an update when I've run through these items.

 

[Balok]

Had zero luck with henkyo carbs and had mine rebuilt with modern goodies to deal with the ethanol fuel. My grandfather was right. "Cheap pays twice." So check out carbs.us. A bit pricey (maybe) but the workmanship of the product is excellent. Even my mechanic was impressed. Always great to help a small business.

 

[HerStang]

Update - Replaced the needle and seat without luck. Pump is not adjustable. As mentioned float was correct...SO

I finally just bit the proverbial bullet and bought a rebuilt 1100. After installing and adjusting it runs just fine. Still need to fine tune it, though. The AC drags the engine quiet a bit at idle, but if when i adjust the idle to account for AC it runs high idle when AC is off. Just need to find the sweet spot, but ultimately it is finally on the road again.

I appreciate all of your assistance and suggestions! I will attempt to post pictures again on my other forum post.

 

[HerStang]

Also, pics have been posted