Holley Carb 6910 CFM?

[78Centurion]

I have two Vac Sec Holley Carbs with 6R (6910) B on top. Does anyone know if these are 450cfm or 650cfm???

[Blown 472]

If the list number is 6910 then it is an 800 cfm carb

[78Centurion]

I didn't think they where that big. I did a rebuild on them and had to buy a Master Holley kit that had several Carb parts and gaskets included. They are on a Tunnel Ram intake for my BBC 454.

[GofastRacer]

List 6910 is a 4165 and it's an 800cfm spread bore double pumper, Rodchester replacement!..

[78Centurion]

They are not Spread Bore. I can't find any info on these.

[Blown 472]

They are not Spread Bore. I can't find any info on these.
Does it have the choke housing still on it? if so what is the "list" number?

[GofastRacer]

Those look like 1850 vacuum secondary 600's!..
http://www.***boat.com/forums/attachment.php?attachmentid=31101&d=1179412799

[78Centurion]

No choke housing. Would it help to get any other numbers on the carbs? I see random numbers all over them.
I want to determine if they are a good carb or should I replace them and with what?

[SmokinLowriderSS]

Welcome to the wonderful world of "someone machined off the choke horn to eliminate the "restriction" (it does not cause) and did not transfer the list number to the carb body again". I would suggest as you get this nailed down, you do yourself and the future owner the favor of stamping the list # back on.
From a dig on the web, you're not the only person to have this exact problem:
Thanks but that doesn't show a carb like mine. I looked the carb over again and it doesn't have a choke horn at all. On the top of the main body of the carb it says 6P 6910 B(or 3). The "6910" have an elongated circle around them.
The next guy at least had the choke horn still on:
I got a hold of this holley and im trying to figure out what size it is. the number i got off of it says 6910. I believe it to be a 600 but cant know for sure. It has vaccum sec. and a manual choke. any help would be appreciated.
i dont think i got the right number cuz i know for sure its a vac. sec. and its not a spread bore. I got the number next to the choke and the where the air filter would be. Is that the right number or is there another one i need?
i looked at the choke horn closer and scraped off some crud and found:list-1850-3 and below that 1215. so i know its a 600 but is it part of the 4150 or 4160 family?
The 4160 has a non-jetted (fixed jetting) metering plate in the seccondaries, and a vaccuume seccondary.
The 4150 has replacible jets and mechanical seccondaries.
At last resort to spec out the CFM, a set of calipers and a call to holley should be able to get the CFM of the main body.
All the list 1850's I am finding specs on, are 600CFM'ers. Apparently no other size.

[78Centurion]

Good info thanks.
I am still learning.
The Carb's still have the choke horns and with a little rubbing I found the numbers.
Both say:
List-1850-3
then below that is 2830.
Are they 600CFM?
Good Carb or bad carb?

[Blown 472]

Good info thanks.
I am still learning.
The Carb's still have the choke horns and with a little rubbing I found the numbers.
Both say:
List-1850-3
then below that is 2830.
Are they 600CFM?
Good Carb or bad carb?
600 cfm vac secondary. If they work run em.

[Blown 472]

Welcome to the wonderful world of "someone machined off the choke horn to eliminate the "restriction" (it does not cause) and did not transfer the list number to the carb body again". I would suggest as you get this nailed down, you do yourself and the future owner the favor of stamping the list # back on.
From a dig on the web, you're not the only person to have this exact problem:
The next guy at least had the choke horn still on:
The 4160 has a non-jetted (fixed jetting) metering plate in the seccondaries, and a vaccuume seccondary.
The 4150 has replacible jets and mechanical seccondaries.
At last resort to spec out the CFM, a set of calipers and a call to holley should be able to get the CFM of the main body.
All the list 1850's I am finding specs on, are 600CFM'ers. Apparently no other size.
No restriction eh? why dont they put them chokes on the hp holleys then?

[GofastRacer]

Good info thanks.
I am still learning.
The Carb's still have the choke horns and with a little rubbing I found the numbers.
Both say:
List-1850-3
then below that is 2830.
Are they 600CFM?
Good Carb or bad carb?
Like I said they are 600's and they are good, but to make the secondaries work effiently you need to connect them together with a vacuum line, Holley has the tops for a vacuum line!..

[GofastRacer]

No restriction eh? why dont they put them chokes on the hp holleys then?
Yes there is a restriction, I wish I still had the time tickets to prove it!..:mad:

[Blown 472]

Yes there is a restriction, I wish I still had the time tickets to prove it!..:mad:
What did you race?

[78Centurion]

Thank you all for the info.
I found the Holley Sec Vac top part # HLY-20-28 at Summit. They are $76.99 each. :sqeyes:
I will have to do it eventually.

[Blown 472]

Thank you all for the info.
I found the Holley Sec Vac top part # HLY-20-28 at Summit. They are $76.99 each. :sqeyes:
I will have to do it eventually.
Or just take them off, use the barb fittings from bimba air cylinders that are very small perfect for 1/4 id hose and drill and tap the tops your self and put the hose between them.

[GofastRacer]

Thank you all for the info.
I found the Holley Sec Vac top part # HLY-20-28 at Summit. They are $76.99 each. :sqeyes:
I will have to do it eventually.
That don't sound right???:confused: But if that's the case I'd just put a fitting in the covers you got done deal!..

[78Centurion]

You mean take them off and drill and tap them so you can thread a mini into the top of the Vac cap? like a 1/4 hose to 1/8 pipe?

[GofastRacer]

What did you race?
First time I did it was back in the car days, 66 Fairlane 390GT was running 14 second flat stock, cut the choke horn off ran 13.99!.. Then did it in a boat on a tunnelram with the 660's gained almost a 1/2 mile an hour!..

[GofastRacer]

You mean take them off and drill and tap them so you can thread a mini into the top of the Vac cap? like a 1/4 hose to 1/8 pipe?
Yep, but less than a 1/4 hose use a vacuum fitting for vacuum hose!..

[78Centurion]

I am going to try and use this or a brass one?
Fitting Size 1: 1/8 in. NPT
Fitting Attachment 1: Male threads
Fitting Size 2: 1/4 in.
Fitting Attachment 2: Hose barb
Fitting Angle: 90 degree
Fitting Finish: Blue anodized
Fitting Material: Aluminum
Quantity: Sold individually.
Notes: Nipple is beaded, not hose barb.
Fitting, 90 Degree, 1/4 in. Beaded Hose End to 1/8 in. Male NPT

[Oldsquirt]

Just buy a HLY-20-73 (http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY%2D20%2D73&N=700+115&autoview=sku) kit. You get the tops set up for balance tube as well as quick change spring capability. $45.

[GofastRacer]

Ok now make it simple, drill a hole in the cover and epoxy a piece of copper tubing in it done deal!..:D

[GofastRacer]

Just buy a HLY-20-73 (http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY%2D20%2D73&N=700+115&autoview=sku) kit. You get the tops set up for balance tube as well as quick change spring capability. $45.
That would be the cool way of doing it!..

[78Centurion]

That will work! Thanks! :)