Carb Sizing/vacuum or Mechanical

[skinny z]

My other thought was that my .028 nozzle might be a bit small for this engine

I can't comment on the squirter size. Just too unique. That said, it seems that timing tends to be the cure my drivability problems. Right advance at the right time.

[Horder]

Do you recall the “HG that your can starts to actuate and then is completely deployed? How many degrees of timing do you add?

[Horder]

This issue isnt a huge deal for me. I only brought it up as the only real issue I had while running this 600 DP.

As well, i had mentioned this issue might not be carb related. But great to have more insight

[skinny z]

Do you recall the “HG that your can starts to actuate and then is completely deployed? How many degrees of timing do you add?

Rough figures (it's buried in a journal somewhere).
Some info as we're not apples to apples.
355, 10.2:1, 288/294, 236/242@.050", 110 LS in at 104 ICL. Wheezy shortblock with what started out at 180 PSI cranking had now declined to about 155 average.
900 RPM idle, 10" vac. At one time when fresh(er), that was closer to 12 at 800.
Advance can set for full deployment @ 8".
Max vacuum advance 14°all in at idle. I don't recall the tip-in point but I'm thinking it was something like 2-3".
Used a can with a large amount of advance and trimmed via a limiter plate.
Initial 14-16°.
Total idle timing ~30°. (Game changer).

[Tom68]

My other thought was that my .028 nozzle might be a bit small for this engine

Bit of cam in a small motor, 28 is most likely a bit small.
Seems just whacking the throttle stationary is enough to show this up, lot of difference between a 28 and a 31.

[rgalajda]

Its a 3310 750 CFM

There are many different versions of the 3310 . What is the number or letter after 3310-?

[Horder]

Unsure at this time. Hes gone to the warm weather for a couple more months. 3310 is all I know.

[rgalajda]

This is the carb I run most of the time.
Engine is 454/500+ HP – Trans 400 Turbo with a 2000 stall converter
1975 Monte Carlo built for street touring
Camshaft is Lunati HFT custom grind on Voodoo lobes 273 Advertised Duration and 227@ .050”
107 LSA
3310-1 780 VS Holley with some work done to it. These are the modifications I did.
Stepped Dogleg boosters ( I machined them ) for better fuel shearing to improve fuel atomization.
Detailed with sharp edges leading into the booster. This improves signal gain.
Entrances on secondaries barrels rounded , and radiusing the choke horn, for air flow
Button head throttle plate screws with ends removed for airflow
Vacuum secondary pod drilled with .035” bypass beside the check ball. ( Thanks to “Tuner “ for this modification ) and Plain spring used . No further adjustments to VS were needed.
All air bleeds and restrictors drilled and tapped
Finished with a complete restoration
I run an A/F gauge so this is the calibration in the end.

Primary jet # 72 reduced to # 69, Sec jet #76 ------ Front and rear power valves 6.5”
Primary accelerator pump nozzle .025”

Primary Metering Block 5721
PVRC .062
IFR .037
Emulsion .028
Emulsion .028

Secondary Metering Block 7003
PVRC .068
IFR .037 moved to front ( was .040 under brass plug at top )
Emulsion .027
Emulsion .027

Main Body
PIAB .078
PHSAB .027
SIAB .028
SHSAB .024
TSR .068
12 degrees initial timing , 32 degrees with manifold vacuum advance at idle
Steady 12” vacuum at idle in gear 800 rpm
Cruise AFR 15:1
Vacuum secondary operation with this setup is outstanding.
Best fuel mileage on a tank of gas was 19 mpg ( without trying hard )

A point of interest is that the 3310-1 is a 4150 model with a secondary metering block , dogleg boosters, has the brass tube in the primary venturi for the vacuum secondary diaphragm, and uses a front a rear power valve. All 3310 models following this were 4160 models with diminishing features.

[Horder]

Well…I see a used 3310-1 close to me that I can pick up for about $175 Canadian dollars. Thats about $130 USD
Seller says he know nothing about it. It has downleg boosters and a metering block. Date code would be from 1974

[lefty o]

for that kind of money, it never hurts to have a good spare. metering block in the rear is a bonus too!

[Horder]

Well… I finally picked up a carb to tune and compare to my 4776 600 Double pumper. Its a Holley 3310-1. Im going to do a full rebuild and add a quick change spring cover. It appears to be very original. Shafts are tight. And suggestions would be great. Ill post the car details again

66 Chevy II Nova 2 door hardtop
Small journal Chevy II recessed oil filter block
.040” 327, forged and balanced rotating assembly
Trickflow DHC aluminum heads 258cfm int 208ex @ .500”
10.2-10.3:1 with .038 quench
Retro Roller 273/278 adv 223/225 @.050” 110 LSA installed at 105.5 ICL .544/.525 lift
Scorpion 1.6/1.5 rollers. Trend Pushrods
1967 Z28 Winters aluminum dual plane
Holley 4776 600 CFM DP
MSD distributor. 18 initial 18 mech 36 total, 10 deg vac adv
1 5/8” headers, 2 1/2” exhaust
Muncie M21
12 Bolt 3.73 Posi
26” street tire

[Tom68]

That'll work nice.

The check ball in the vac sec diaphragm housing can hamper secondary opening, you can dig a deeper groove where the ball sits for quicker secondary opening if it needs it.

[Horder]

Any power valve or preliminary jetting ideas? Engine makes 14-15 in/hg at 800 RPM. Do you guys like the secondary powervalve as delivered?

[1980RS]

In a test way back in 1996 with my old 396 in the car I ran a back to back test of a 3310-1 and 3310-2 all out of the box settings except for both carburetors had yellow springs with the check balls removed. The difference was the -2 was 2 tenths quicker and 1/2 MPH faster over the -1. Most likely the intake was the culprit as I think the -2 got a better signal at the time running the old canter Eddy Torker 2.0

[rgalajda]

Any power valve or preliminary jetting ideas? Engine makes 14-15 in/hg at 800 RPM. Do you guys like the secondary powervalve as delivered?

Is this a 4speed car?