Edelbrock 1901 and 454 BBC

[deric83616]

Bought the your book, bought your kit, Thank you for those, and after practicing on several cores I'm starting on mine.
I bought the 1901 new and it has always had a nozzel drip. During a Christmas Parade this year the car acted like the choke stuck closed, it wasn't. The car would not Idle, the only way to get it started was to hold the accelerator down and crank. The car was flooded, would not clear and ran extremely rich.
The motor is a 454 in a 71 Corvette with A/C and Manual Trans the motor is .060 overbore, 9.5-9.7 static compression. CompCams High Energy 268 (.485 lift and duration 218 at .050 both exhaust and intake), the heads are mildly reworked, the intake and exhaust are stock. Before the over rich condition started: Idle vacuum was 15 inches and stable at 600-700 RPM. The mixture screws have little or no effect. Cruising down the road the car felt like it was surgering but ran great went the secondaries kicked in.
The 1901 Carb was out of the box from Edelbrock. On tear down, the only thing I found was that both Main Well Bleed Tubes were completely pluged. Using a wire gauge to clean the opening the lower opening (smallest) appears to be approx .026. What do these tubes do and is the opening ok for my appliation.
Idle Tubes .032
Idle down .042
Upper Idle bleeds .070
Lower Idle bleeds .041
Idle bypass .070
Idle mixture screws .070
Main Air bleed main body   .052
Jets 69
metering rods 49b
My measurements are somwhat approx as I use drill bits, welding Tip cleaners and wire feeler gauges as go no-go gauges.
I'm looking for a starting recipe, those in the book appear to be SBC.  I believe I need to open things up a bit. I'm looking for a good running motor, squeezing ever ounce of performance out is not my goal.

Merry Christmas and TIA
Dave Erickson

[Cliff Ruggles]

Dave, Edelbrock used quite a few different calibrations for their carburetors.  The .041" lower idle airbleed I have not seen on any of them. 

What are the upper main airbleeds sizes in the airhorn?

In any case, nozzle drip indicates not enough idle fuel for the application.  Could need more idle bypass air as well.

Being a big or small block really doesn't matter as far as the "recipe" used.  The engine idle characteristics are what's really important.  Do you know how much vacuum the engine is producing at idle speed?.....Cliff

[deric83616]

Thanks for the reply
Vacuum at 700RPM 15 inches
Main air bleeds in the Air Horn .050
lower Idle bleeds are really .070
Don't know for sure what the following refer to:
Secondary POE Well Restriction (is this the small hole between the main well and the secondary well?)
Secondary POE Restriction (Is this the small hole in the main body above the secondary flaps?)
Secondary Brass Tube Restriction (Is this hole in the botton of the large outer brass tube in the air horn?)
Can a divorced choke be converted to a hot air/Electric choke using parts from hot air style carbs.
There is a Vacuum port on the choke side main body of my carb that has a brass tube installed, should that port be plugged.
My Main Well Bleed tubes were plugged The restriction at the bottom appears to be about .025. What should it be or are these tube the same as Secondary Brass tube restriction.
Thanks
Dave

[Cliff Ruggles]

POE well restrictions are the holes leading to the wells.

POE restrictions are in the airhorn.

If I read it right, you have .070" upper and lower idle airbleeds, and .032" idle tubes with .042" idle channel restrictions.

Increase to at least .036"/idle tubes and .046"/down channels, and test it again.

If the main airbleeds are close to .050" for each pair, the .069" main jets and .049B metering rods may be a tad lean for the big block.

The factory used .071" main jets and 45B rods with the APT adjusted up some for the pre 1970 big block applications.

It is not practical to converter those to electric chokes (on the carburetor).  They make an electric choke unit for the intake, but we don't sell them here......Cliff