Holley 670 set up

[Paul_G]

I put a used 670 SA on my 383. The car has a manual trans. Carb is rebuilt, clean inside and out, cleaned out all the passages.

Carb is back to stock, jetted Pri 65, Sec 68, 31 squirter, Orange pump cam in #1 hole.

Squared up the transition slots on both the primary and secondary sides. Set idle mixture screws to 1 1/2 turns out to start. Set float levels to just a dribble out the hole. Engine was idling way to low, around 600 RPM. Opened the secondary side throttle blade first trying to raise the idle. Had to open the primary side as well to eventually get the idle up to 800. Put the vacuum advance on the manifold side in another effort to raise the idle.

Adjusted mixture screws to highest vacuum, about 1 1/4 turns out. Adjusted accel pump lever to zero free play. Ign timing at 18° base, 34° total.

The problem, when letting the clutch out the engine will drop rpm and die way to easily. I have to slip the clutch way to much to get the car moving, after that it is great.

I tried putting larger pri jets, 67's. No help. Went to a 35 squirter, still no help. Took the Holley off and put an Edelbrock 850 on. The 850 is too much for the mild 383, but, it does not die when letting the clutch out, and do not have to slip the clutch near as much as with the 670 Holley.

Any ideas whats going on with the 670?

 

[451Mopar]

On my Street Avenger, the idle restriction orifice in the metering block was small, I think around 0.028", and the carb would go lean in the transition off idle.
I opened up the restriction to 0.032" and that helped.
Also, the power valve restrictions in the metering block were fairly small also.

 

[Paul_G]

I found some casting flash in the metering block idle channels. I drew green lines in the pic where the restriction was. The pic is not my metering block, a pic from the internet. It was blocking about 1/3rd of the channel. Cleaning that up helped improve the lean condition on transition just a little. Next thing will be to open up the orifice.

View attachment 1131098

 

[451Mopar]

Pull the main jets and make sure there is no debris in the channel behind the main jets. I had that happen too. I'm worried about Holleys Quality Control?