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FE Power Forums => FE Technical Forum => Topic started by: DEANs427 on March 19, 2019, 12:03:23 PM

Title: HOLLEY QUESTION
Post by: DEANs427 on March 19, 2019, 12:03:23 PM

LIST 3916-1S, setting this carb up for use on top of a 4-71 supercharger, noticed main body has 1/16+ drilled passage to OUTSIDE in each venturi about 1/2 inch up from base plate !? original owner of carb said it came that way, looks factory, plan on plugging them...
opinions, comments, suggestions....

Title: Re: HOLLEY QUESTION
Post by: thatdarncat on March 19, 2019, 01:55:41 PM

The small holes on the side of the Venturi to the outside of the main body are original on many Holley carbs. I have a few that way, although I don’t think I have that particular one to compare. This subject came up here a few years ago, I don’t remember if Barry R. or anybody weighed in on the engineering theory behind them. I’ve always just left them be on any of my carbs that have them. If we knew for sure what the purpose was it would help in deciding whether to leave them or plug them.

Title: Re: HOLLEY QUESTION
Post by: thatdarncat on March 19, 2019, 02:09:55 PM

I assume these are what you are describing? Just an example for anyone who hasn’t seen these before. These are on my 850 Center Squirters.

(https://i.postimg.cc/LsfdRBgS/72992-C90-0-B88-480-D-A8-D6-4851-C3-AFEE6-D.jpg) (https://postimg.cc/sBVH4WJH)

Title: Re: HOLLEY QUESTION
Post by: fordman460 on March 19, 2019, 03:39:17 PM

Helps evaporate fuel vapors during hot starts.
Mine are all open. No problems here.

Title: Re: HOLLEY QUESTION
Post by: gt350hr on March 20, 2019, 09:16:07 AM

 They are on list # 3255s and the -1 version too.

Title: Re: HOLLEY QUESTION
Post by: machoneman on March 20, 2019, 10:17:20 AM

That would never fly as the EPA started new emissions regulations. Wonder if they got plugged then?

Also I wonder if a backfire could cause an engine compartment fire?

Title: Re: HOLLEY QUESTION
Post by: fordman460 on March 21, 2019, 10:15:02 AM

Had a few backfires over time with My 3 barrel on different applications. Holes are so small that it all come out the top as any other carburetor does. No air filter as this usually happened while setting distributer timing on first start up.

Title: Re: HOLLEY QUESTION
Post by: DEANs427 on March 21, 2019, 12:23:00 PM

I see the holes as a possible path of hot dirty underhood air to my blower, I plan on taping them off.
Using this carb at strip only, running 3310 for street and cruise

Title: Re: HOLLEY QUESTION
Post by: gt350hr on March 22, 2019, 11:38:36 AM

You could plug them with lead shot. I have seen them closed by Holley engineers that way.

Title: Re: HOLLEY QUESTION
Post by: boneyard51 on April 05, 2019, 10:57:57 AM

Dean , are you putting a blower on the “Ghost”? 



Bones