[80PontiacWagon]

Hey guys recently got a Holley 950 CFM 3 barrel carb.
I am looking for a rebuild kit to help bring this carb back to life.
But when I called Holley today they gave me a part number 3-405
but when I looked it up, its just a universal rebuild kit, for a 4 barrel.

I was wondering if anyone out there has rebuilt one of these and remembered
what kit they used. The number stamped on the top is. 3916-1S

Thank you to everyone for all your help.

[ericnova72]

I have two of these and I love them. The # that Holley gave you for the kit is for a four barrel, but it is your only solution as these carbs have been obsolete for so long that a specific 3 barrel kit is no longer available. Not to worry though, the solution is simple since these carbs are just basically an 850 with the divider cut out from between the rear barrels, so all it takes is a razor blade to cut the divider out of the main body gasket. Simple, no??

The bigger problem you will have is coming up with the correct vacuum diaphram for the vacuum secondary. It is a lot larger than a normal Holley diaphram and no longer available.

There are only three solutions - you can swap to the complete vacuum secondary housing of the current Holley size and style, swap to the vacuum housing from the Mopar 2 barrel "Six Pack" three 2 barrels carbs, or modify the "six pack" diaphram to fit in the 3 barrel stock housing.

Of these three methods I have only done the modify the six pack diaphram myself, it is a bit of work. I have not confirmed that the six pack complete housing assembly will interchange but it appears that it would. I have seen online the swap to the current size Holley vacuum secondary housing but can't confirm if the smaller diaphram will open the rear barrels correctly or at an acceptable rate.

I was told by a Holley rep at a race that Daytona Parts Company in Florida may have some of the actual 3 barrel parts but never confirmed it.

[80PontiacWagon]

Wow thanks for all the help, thankfully the diaphram for my secondary is not torn and still holds strong, So your saying that the part number Holley gave me will work, just need to do a little cutting?

[ericnova72]

Yes, all you have to do is cut the divided section out from between the two rear barrels of the main body to baseplate gasket so that it has one big oval rear hole to match that rear barrel of the carb. A 30 second job with a razor blade or Exacto knife. Basically all Holley did was take the 850 Vacuum Secondary carb and remove the divider between the two rear barrels to make the 3 barrel. The front half of the carb is exactly the same as an 850.

You will also have to do a little gasket hole punching on the rear metering block gaskets to make sure the gasket matches the location of the feed holes into the rear boosters, Holley also moved the rear boosters closer together to make up for the missing divider between the rear barrels. If you look at the carb and the original gaskets it is obvious what you need to do, two 3/16" holes in the rear metering gasket are about 1/2 a hole off.

The rest of the gaskets are the same as all other basic Holley Modular carb design gaskets such as the 3310 750 vacuum and the 4776-77-78-79-80-4781 double pumpers. Such is the beauty of Holleys design.

[80PontiacWagon]

Thank you so much for all the help. Just ordered the rebuild kit and a can of bronze carb paint to make it look and run like new again.