Ive got a 71 Dart with a 225 slant in it. I have put a comp cam milled the head .050, and re ringed it with new bearings. My problem is that i have the lightest secondary spring in my Holley 390 and they are still not opening up. Is this normal for this size engine?

My 390 did the same thing. I thought it might have been load sensitive as sometimes it would open and others not. Never did fix the problem with everything I tried. The 500 AFB I replaced it with never fails to open.
Good luck and I hope you figure it out.

they wont open when the car is parked and you are reving or they wont open under a load?

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1966 Plymouth Valiant, 225, 3 on the tree, 8 1/4 3.21 sure grip, hyperpac, holley 650dp, holset h1c

They wont open under load, I got home and checked and I had the light yellow spring in, so I switched to the white spring. Ill see tomorrow if theres a change.

1) What is your vacuum reading when you get on the go pedal?

2) What base gasket did you use?

One other item to check before the spring change...

With the car parked and engine off, pull the throttle lever to full open, then with your other hand rotate the secondary throttle shaft...the secondary shaft is locked out by the linkage at certain primary throttle positions. On my car I have also had to bend the linkage a little in spots to properly clear the manifold...if both plates can't open 100% then you need to find out why and correct that first, if it is the case.

Another thing to check is the seating of the secondary vacc. lever and diaphragm, if it is installed incorrectly and covers the regulating orifice, or has a hole/tear in it, or didn't seal properly when installing the new spring or the secondary spring quick change kit the secondaries will either not function or be very "lazy", similar situation exists if the little cork gasket between the body and pod is no longer sealing things (I keep spares when I regasket my carbs every so often).

-D.Idiot

In addition, the Holley needs the Mopar throttle lever kit in order for the primary to open fully. If the primary doesn't open most of the way, the secondary will not open.

CJ

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Part of Tyrde-Browne Racing

This is very correct...although I can say that with a little savvy and 2 correct size washers...a carter BBD or TQ throttle stud can be installed in a pinch...

-D.Idiot

DI: Also make sure that the hole in that little cork gasket is open or the secondaries will never open. Guess how I know that little glitch.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I used the holley base gasket that came with the carb, the throttle linkage I used is home made by me, and last time I checked it opened completly and with good clearences. I also checked out the cork gasket when I replaced the spring earlier, and it was all there and seated properly.

I headed off from the house today and the secodaries did open up but it was running way too lean. So I cheched the float level and it was way too low and I got it adjusted. Ive just got a few little adjustments to make now and she should be running pretty great.

Secondary fuel does get overlooked, float level in any carb is pretty critical...in the holley it can cause a main lean out or fatten it up at the turn of a screwdriver and 5/8" wrench...but is not a permanent solution.

-D.Idiot