Holun,

You might try double gaskets under the fuel discharge nozzle assemblies.  It's not unusual for these assemblies to become warped due to being overtightened with that single screw that holds them in place.  You can also try just making the gasket out of thicker material in the event you don't have some extra gaskets laying around.  The idle feed holes are located on the outside ends of these assemblies so if there is going to be any leakage due to warpage, it will happen first at the ends.

Lorena, Texas (South of Waco)

I put the extra gasket on the clusters, no effect. weird.

I'm assuming that you can screw the idle mixture screws all the way in without the engine dying or having a noticable effect on the idle quality.  I'd suggest pulling the carb back off of the engine and looking at the position of the primary throttle blades in relation to the idle transfer slots in the primary throttle bores.  This is a good time to also check that both blades are positioning themselves the same in both bores.  Unequal or mis-synchronized blades will cause their own set of problems.  If you have more than 1/6" inch of idle transfer slot exposed with the blades in the idle position, then you'll likely need to get the primary throttle blades closed up some more without killing your idle speed.  There are two easy ways to go about this with the first being to just open up the secondary blades a bit more to allow the primary blades to be appropriately closed up.  If the secondary blades are already opened up a significant amount, then you can try drilling a 1/8" hole in each primary throttle blade to allow the blades to be closed up some more.  These holes allow some extra air through the carb without having too much idle transfer slot exposed.  If this helps but does not completely cure the problem, then you can step the holes up another size but you'll need to be caustious in doing this modification as its difficult to reverse.  This is not an unusual modification when installing a camshaft that causes the idle speed manifold vacuum to drop off.

Lorena, Texas (South of Waco)

where do I drill? as far away from the idle and transfer ports as possible?

So I drilled some holes on the throttle plate, first I drilled 1/16 ones, away from the idle and transfer slots, idle screws have no response, then I open them up to 1/8, vola, it works, if I turn the screw all the way in, the engine will die.



no change in idle quality, I fiddle with the idle screw where it gets the best vacuum and highest rpm,.

The ideal location for these holes is half way between the throttle shaft and the edge of the throttle blade on the idle transfer slot side of the blade.

Lorena, Texas (South of Waco)

so I did some more fine tuning today, adjusting the seconday action, on 1st gear hauling ass, I can feel the seconday comes on suddenly at about 2500rpm, for what I understand if the spring is too weak (opening too soon)it should graduly gets stronger as the rpm climb, but this is sudden surge of power, 2nd and 3rd seem like a smooth transition, I dont feel a sudden power surge nor bog then surge from opening too soon.



I already put a 2 step weaker spring in there, but in first gear, the sudden secondary action didnt change, comes on at about 2500rpm, I guess the 1st gear load is not enugh to have the seconday come on at below 2500 for a smooth transition?

HoLun  - are you still down at the 4.5 power valve? Now that you've got the idle screws working, the extra enrichment you get from the valve might be needed to make the engine accelerate harder?

 
 Steve Metzger       Tucson, Arizona

well I guess it doesn't matter now, I just destoryed this carb by putting it on and removing it 1 too many time, I cracked the carb flange, now I need another one....

So I brought myself a Holley 470 CFM Truck Avenger carb, I notice right away, the idle is much much much smoother.



now I need to tune it better, since its calibrated for a truck.



anyone know what color secondary spring I should be using for a 3700lb car?



also how do I adjust the accelerator pump? the instruction didn't mention anything about that