[vicgto]

I am planning on installing jet extensions on my 950 HP, has anyone clearanced the nitrophyl float using a Dremel or similar tool, or is this not a good idea?

[25stevem]

That will work with a wood cut Burr in the tool, but then you need to seal up your work a fuel resistant epoxy.
This makes the float heavier then stock and slower to respond to fuel level changes.

Floats can be had that are made for jet extensions however and that’s the route I would go with.

[Scott65]

In the past you could buy the notched float with the jet extensions in a kit. Just an option to consider.

[KGTO]

Originally Posted by Scott65

In the past you could buy the notched float with the jet extensions in a kit. Just an option to consider.

That's what I've done too. Still available

[Scott65]

Actually, have you opened up the rear float bowl yet? I thought Holley had at some point started sending these out equipped with jet extensions? Maybe not anymore, idk. Might be worth a look if you haven't already.

[Tandyman]

Holley kit 116-10 or AED 5896 is what I have used in the past . I believe it was not much more than for just the notched float . About 50 bucks or so I recall .
Glenn

[vicgto]

Originally Posted by 25stevem

That will work with a wood cut Burr in the tool, but then you need to seal up your work a fuel resistant epoxy.
This makes the float heavier then stock and slower to respond to fuel level changes.

Floats can be had that are made for jet extensions however and that’s the route I would go with.

I would expect the float to be solid through out like a Q jet float, meaning it would not require epoxy?

[vicgto]

Originally Posted by Scott65

Actually, have you opened up the rear float bowl yet? I thought Holley had at some point started sending these out equipped with jet extensions? Maybe not anymore, idk. Might be worth a look if you haven't already.

I have the carburetor apart, it doesn't have extensions.

[vicgto]

I currently 60 foot low 1.6's without jet extensions. Is anyone 60 footing 1.5 or less without jet extensions? Just wondering at what point it really become a necessity to install extensions.

[Tom Vaught]

Have you trimmed your White Plastic Vents about 1/2" shorter vs stock Holley length
and restored the opening "square" at the top of the modified vent?

Tom V.

[Tom Vaught]

Post #71 of my Holley "Sticky" goes into how to properly modify the Holley Bowl Vent
Whistles. Info for the board.

http://forums.maxperformanceinc.com/...y+Vents&page=4

Tom V.

[455-4+1]

I have clearanced them and sealed with clear nail varnish before, no issues and minimal weight change.
This is on both Holley Std and Brasewell road race with the trimmed corners.
I also prefer to use a BLP style extended jet, rather than the hex style extension that adds a larger volume of fuel in the now "extended well" that has to be accelerated.
The BLP style leaves the jet in the original location.
We did not trust the slip on flattened extensions in our application either

[blueghoast]

Originally Posted by vicgto

I am planning on installing jet extensions on my 950 HP, has anyone clearanced the nitrophyl float using a Dremel or similar tool, or is this not a good idea?

Do you have a bad stumble off the line.
Is this why you want jet extensions?

GT

[455-4+1]

Are you running a rear PV ?

[vicgto]

Originally Posted by blueghoast

Do you have a bad stumble off the line.
Is this why you want jet extensions?

GT

I don't have a stumble currently with my 3310 vac secondary. I recently picked up a 950 HP and currently have it apart. I'm considering proactively installing the extensions. On post #9 of this thread I asked if anyone has 60 footed in 1.5 or less without extensions. I'm trying to figure out at what point it typically becomes necessary.

[vicgto]

Originally Posted by 455-4+1

Are you running a rear PV ?

No rear power valve, 86 jets.

[25stevem]

What do you have for the basic fuel system in the car now?
If your still running thru the stock or even a slightly bigger fuel system then if your motor is making enough Hp you might find that the reduced fuel bowl volume in conjunction with being at the limits of volume that your basic system can provide will create a secondary side fuel shortage.

I also can’t see why with the times your car is running that you have no power valve in the back.
To me your motor due to the stall speed you have and the cars gearing does not rev up fast enough nor high enough at leaving the line to not having a power valve being a plus, but a disadvantage!

Your vacuum secondary’ carb in and of itself makes for running a blocked power valve a waste in my opinion.

[Formulajones]

Originally Posted by vicgto

I don't have a stumble currently with my 3310 vac secondary. I recently picked up a 950 HP and currently have it apart. I'm considering proactively installing the extensions. On post #9 of this thread I asked if anyone has 60 footed in 1.5 or less without extensions. I'm trying to figure out at what point it typically becomes necessary.

Both of our A-bodies 60 foot in the 1.50's when both cars had 950 HP carbs on them. Neither had jet extensions. Ran them that way for many years. When dad switched his car to a larger engine with more power (same carb) he had a couple 60 foots in the 1.46 or 1.48 range.

Not a bad idea to add jet extensions if you want, but I'd just buy the notched floats if I were doing that, because it's not like it's expensive. Modifying floats and trying to epoxy them just goes down a rabbit hole with potential problems later down the road that I don't want to deal with.

What I found both cars really needed at this power level and 60 foot capability is a good fuel delivery system. -8 line to and from with a good Walbro pump inside the tank supplying the fuel.

[ta man]

When my car does a sub 1.55 60 ft the cigarette lighter flies into the back seat. Think about where the fuel in the rear bowl is going, away from the jets and if one still has a PV away from it. Why risk a momentary lean mixture? Vic's car has the potential to run sub 1.5's eventually its a no brainer to set it up properly. Holley carb 101.

[Tom Vaught]

Originally Posted by 25stevem

I also can’t see why with the times your car is running that you have no power valve in the back.
To me your motor due to the stall speed you have and the cars gearing does not rev up fast enough nor high enough at leaving the line to not having a power valve being a plus, but a disadvantage!

Your vacuum secondary’ carb in and of itself makes for running a blocked power valve a waste in my opinion.

Agree because #3310 carbs (750cfm/780cfm) come stock with a metering plate.

If you upgrade to the Holley replacement Metering Block and remove the 3310 vacuum secondary metering plate the replacement block does not come with a provision to easily install a power valve. It is not even drilled and threaded for the PV. So no power valve capability on the #3310 carb unless you use a second #3310 primary metering block on the rear of the carb.

Many of the 950 HP carbs have a Power Valve on the rear metering block.
Most remove the rear PV, install a plug, and jet up accordingly. (6 sizes)

"Your vacuum secondary’ carb in and of itself makes for running a blocked power valve a waste in my opinion"

Read again above, 25stevem;6416696

#3310 factory carbs do not use Power Valves on the secondary side.
(metering plates are used, not metering blocks.)

You are mixing the 950 HP capabilities with the normal 780 CFM #3310 Vacuum carbs capabilities in error.

Tom V.