[bb67H-D]

Checked all idle passages per Tom M.[thanks for the info!] and all were fine.

I installed carb and was able to get good idle but again with mix screws out close to 3 turns with best vac a little more out..

I did spray starting fluid around carb ,manifold etc.. not any affect.

I then put wire in the idle bleeds and could get best vacuum 1-2 turns out on mix screws.
I didn't get too accurate as the wire was just temp and I may tap the bleeds for screw in.

I tried a couple different size wires thinner to thicker wire and the thicker wire would have less turns on the mix screws for best vacuum.

Using the wire I also got a little higher vac reading than without 1" tops.

Is there something else or just tap and put smaller bleeds in?
I don't want to mess with the IFR as the idle bleeds seem easier to work with .

If I mess up the carb I have the 800 dp which has worked just fine for many years .

 

[Tom Mobley]

why not just leave it alone? who cares how far out the screws are?

have you checked that somebody didn't open up the secondary idle a little? any holes drilled in the throttle plates?

will it idle down to 500?

 

[bb67H-D]

I thought anything over 1.75 - 2 turns out was not good,
but I do have about the same vacuum @ idle as the 800dp.
just 3+ turns out w/ the 3310.

I don't think it will idle to good @ 500, 700 idle yes
Cam has 236/246 dur@.050 so vacuum is 11"-12" idle 950 -1000 rpm.

I set timing @ 700 so mech.adv. is off. 19*base w/o vac.

I will put it back on and adjust for best vac leaving all alone and then drive and see how it works with my engine, I am sure some pump, jet adjustment will be needed.

Blades are not drilled .

The rear blades are below the T-slots so they should be fine and I couln't budge the adj. screw anyways.
I may try harder on adj. screw as to make sure the rear blades are 1/4 turn from seat.

Botton line ,if I get decent vacuum even @3+ mix turns engine does not care?

 

[1968 hot rod]

pop the brass restrictors out and shallow tap the holes w/a 10-32 tap
drop the idle air bleeds to .065Ø
I use brass set screws to do this.
But you can sub steel set screws,you want to heat those to cherry red to soften them before drilling

 

[bb67H-D]

Put the 3310 on again today.
I was able to get 11" vac @ 2 3/4 to 3 1/4 turns out 950-1050 rpm and good idle with less fumes than the DP.

Went for a drive/carb shake down run & ran very well.

Pushed it a little hard and plenty of rubber in 3rd gear [I live in the country but still rarely do this].

Not the bite/ response of the DP, but this carb feels good ,
different than the DP that I've had forever but a little more work
and a cleaner idle & better mileage should be on tap.

Oh, and next time @ the track I will run both and compare.

 

[Tom Mobley]

sounds pretty good to me.

I'm afraid that if you start drilling and installing bleeds and stuff you'll end up spending a whole lot of time and frustration and not really have anything much to show for it. No fun there unless you're a glutton for punishment like me.

However, I think the bite/response should be better. compare the sizes of the primary squirters, if the one on the 800 is bigger swap them and give it a drive. If not better put them back. If it makes it worse find one a little a little smaller than what you have now and try it.

 

[kettbo]

My 3310s I have had like more than the factory squirter....31s hit well

 

[Xtreme70SS396]

If you're willing to go through this much work on the VS carb, why aren't you willing to do the same to improve the characteristics you don't like about the DP?

If you clean up the idle on the DP your MPG will shoot up, MPG is right-foot based IMO, no magic to it between carbs.

 

[69-CHVL]

There was one 3310, or maybe it was a 80508 (same carb basically) that required me to have the screws almost out 3 turns. Couldnt figure out why, but that's what she wanted, and it ran awesome.

I would put off the drilling and tapping until its a last resort. I been through all of that, and never really ended-up better off. Sure, I could lean out the target cruise area, but somewhere else in the curve got screwed-up. This is especially noticeable in a stick car, as you have the motor loaded down from just off idle all the way through WOT. I found that the best running calibration is...suprise...the factory calibration! Auto cars are much more forgiving IMO when it comes to carb tuning.

 

[bb67H-D]

The 800DP has been on the car since I had 396 rebuilt back in '88 and has always had a rich idle even with t-slots somewhat square and 1.1/4 out on mix screws.
After new valve train and going to a 110 from a 114 LSA the MPG seemed to drop a little and the idle a little more rich but still very responsive.
Both cams have the same dur. 236/246@.050 so I think idle will be on the rich side anyways.
I don't think much more can be done to the DP.
I do think its best not to touch the bleeds on either carb.
I really never paid much attention to carbs as the DP always worked fine .

So going 3+ turns out for idle on the 3310 just didn't seem right and air bleeds was suggested and the two carbs have much different size prm. IAB's which concerned me and I found out 3310's have about a .070 IAB stock which mine has.
DP's much smaller.
The 3310 idles great @3 turns out and plugs look fine so I guess all is good and if needed tune the pump, jets etc.. as I only drove about 7 miles.

I thought I would try a VS carb and an "era correct" 3310 [1968] VS. seemed to fit the bill.

I will search this site & holley's for VS tuning.