Now that I live in a college town, 90 percent of my driving is basically idling around town, having to stop constantly for pedestrians. This carb is just not liking this, as sometimes if I stop very abruptly after a perioud of below 2000 rpm driving it will flood and I have to let it air out for a minute. Just wanting to know what I should go with as far as a second carb that I will run on the street, keeping the DP for the track. Motor is:
383
Sportsman II heads, 64 cc chambers, 2.02 &1.60 valves, gasket matched
Comp 292s solid cam: int. & exh. dur@050 248 .560 valve lift w/1.6 rockers, 110*lobe separation
1.6 roller rockers
Edelbrock Performer RPM
Tranny is rebuilt 700r4 with a 2800 tci stall, but I'm getting ready to install my 3500 vigilante
Gears are 3.something, forgot the number but its factory.
Im just looking for something that will perform off idle and vacuum secondaries, just more streetable.
Still looks stock though...

 

"...Comp 292s solid cam..."

That's your "streetability" issue, not the carb. If the carb is flooding, you need to fix the fuel delivery issue. Pressure should be no more than 6 psi, fuel level should be so that it just dribbles out of the bottom of the site holes, idle mixture properly adjusted, needle & seat able to handle the load, etc.

I took the '57 out of the garage yesterday since it was sunny and 70 degrees (and to show off to the daughter's boyfriend). Stop & go, cruising, full power - no problems. And I haven't even re-tuned it back for altitude after Pomona yet.

There is no particular reason that a strip-tuned carb can't run well on the street, even in stop & go.

 

You can cure your stalling and low speed problems by dialing in the carb and ignition advance curve to match your rough idle camshaft.

use #70 primary jets use #80-83 secondary jets.
switch the primary power valve to a 3.5" or 4.5" rated valve. This will keep the P/valve closed at idle.
lower the fuel level in the float bowls a little , to just below the sight plug instead of the holley recommended "just dribbleing out"

recurve the ignition mechanical advance to get 24 degrees initial timing and 34-36 deg total at max advance This involves limiting the mechanical travel of the mechanical advance weights. (welding up the pin slot in a stock GM HEI)
select a medium tension advance spring pair that allow full advance at 3000 to 3500rpm. ( the real light ones are unstable at idle)
Retain and use vacuum advance ( you may have to limit the travel of the advance linkage to get 10-15deg at high vacuum. Ported vacuum source usually works best.

Recurving the ignition for more initial advance at idle will allow you to close the carb throttle plates down to only reveal the edge (.030") of the idle transfer slots and give correct idle and responce with your big cam.

You would have to do all these mods to a vacuum sec carb reguardless so save your money and just dial in your DP carb properly.
Do this and you'll find the idle to be much cleaner and much more stable at low speed. Get a good hi flow inline fuel filter.

 

Thanks for your replies. I guess I should have referred back to my Holley tuning book before jumping to conclusions. But just to get things straight, a mechanical secondary carb will not inhibit daily driving if properly tuned? For some reason I am under the impression that the mechanical carbs are not as friendly as vacuum, but since I have no data to support this I cannot state it as fact. I will try some of the Missouri fbody forums, but if any of you live around Columbia MO and would consider helping me tune this thing I would provide beer and lunch.
Thanks,
Drew

edit: My distributor is an MSD ready to run, I am running a Blaster 2 and 6AL, and the distributor doesn't use vacuum advance.

 

Only time a mechanical secondary will give you problems over a vacuum is on sudden applications of WOT. Kicking in the secondaries from an idle is one example.

 

Yes, get back into carb tuning 101. Make sure your PV are correct to your vaccum, floats are set correctly, jets are where they're supposed to be, and what I found out last year, be sure your running the proper heat range. I had similar issues when temps cooled down with it loading up at a big race, that night with everybodys suggestions I stepped up 5 heat ranges and car ran MUCH cleaner when doing alot of part throttle driving.

I'd put my car against any fuel injected/VS stocker set-up as far as driveablility goes....but mpg now that's a different story and I wont go there

 

Your msd R to R distributor has an adjustable mechanical advance curve. Set it up as discribed above. (more initial at idle) Consider switching to a vacuum advance distributor.
The vacuum advance at part throttle cruise is essential to
efficient street cruising both in terms of fuel mileage, proper combustion, controling engine temps and keeping the plugs clean. (stalling , response problems) the MSD6 will not cure this, just mask it over time. ( the short plug life and drivability problems will keep cropping up untill you get the ignition and carb dialed in.) Set your car up for efficiant street driving.

A non-vacuum advance distributor is fine for racing or marine use cause the engine is always under load. But street cars spend most of the time idleing and cruising and Part Throttle. Correct part throttle ignition advance is essential. (vacuum advance).

You could run a modified GM HEI vac advance distributor using the MSD 6 and get the dual benefits of the large HEI cap, and CD multi spark along with vacuum advance. This combination works well in an application like yours.

There is also a R to R MSD that has vacuum advance and a
internal high output ignition module and fully adjustable advance curve. It is a self contained hi performance hi out put inductive discharge ignition system. Its all the ignition you'll ever need in a street car. No MSD 6 box required.
This is the type if distributor you should be using.

A holley DP is not inherantly a bad street carb. But like any carb it needs to be set up to operate properly and dialed in to work with your combination.
What spark plugs are you now using?
This is all stuff you can do yourself.

 

You might want to look at a book called "Super Tuning and Modifying Holley Carburetors" by Dave Emanuel. In there is a short section called "Double-Pumpers for the Street". He makes some good comments on things to do to improve the street manners. Since the 4700 series was always an aftermarket carb, most of the time the idle circuits are a bit rich and they have smaller PVCR making you jet higher, which in turn makes part throttle a bit richer. He goes on in more detail, I was just paraphrasing some of it. See if you can read through that part at a bookstore, or buy the book (it is a good book).

 

Thanks for the input, I didn't mean to imply my distributor is not a vacuum advance unit, in fact it is. I bought the engine from a guy who had it in more of a strip/occasional street cruising car. He said the distributor was locked out and to just leave it that way, but it does have a vacuum canister on it, only it's capped off. How would I even start to change over to vacuum advance on a locked out distributor? And I'm running Accel 274 plugs.
Thanks,
Drew

 

He probably only locked out the mechanical advance. The vacuum advance would most likely start working just by hooking it up.

For street use, the mechanical advance provides benefits just like the vacuum advance does. It's better to get both of them working.