Holley 390 help

Hey all, Just wondering if anyone has written down what size jets and power valve numbers they are running on there v-6s. Ive got mine running ok good but I think I might need to mess with the power valve and jets to get it dialed in. Just checking to see if someone here that has theres dialed in, could tell me what they are running?
This is my setup: Stock 225 with holley 390,offy dual port intake, Hei, and stock exhaust other than new magnaflow muffler and slighty larger exhaust pipe (2inch I believe).
What is going on is that I have a slight flat spot when giving half throttle and also im getting really bad gas mileage. Runs great when giving full throttle or very light throttle. Starts fine, idles fine too.

 

I use a 5.5 power valve here in Colorado. The stock one requires too much vacuum to open the power vave and it leans out at part throttle. I don't remember what jets I have off hand. I'll have to look it up. I have the same carb-manifold set-up as you and headers. I added a upside down U shaped piece of fuel line with a 1/4" hole in the top of it to connect the float bowl vents to help with the flooding problem that Holley 4 barrels have when going uphill or downhill. Mileage isn't great for sure

 

anyone ??? still getting the same probs

 

I ran one on my Chevy V-6 and had the same problem. I switched to a Q-jet 4bb.

 

You should be able to tune it up so that it runs fine on the street. The power valve should only come in to the picture when you are running at part throttle with low vacuum (ie a load). I presume you are unhappy with the acceleration at part throttle.

First I would check to see if my overall jetting were ok. The easiest way to do this is to check the color of your spark plugs. Next set your idle mixture to best lean idle, and set the idle speed. Then I would use Holley's instructions to pick the correct power valve based on your vacuum readings. Check the tech library for how to do this: http://www.holley.com/TechService/Library.asp Finally, if you have a bog when you goose the throttle, adjust the pump shot. Or adjust the secondary spring or jetting so that it opens slower or is richer. The secondary is vacuum operated and tunable - if it opens too quickly, the lean condition will cause a bog.

Holleys are not very complicated to tune... other than the jetting, pump shot, power valve and secondary spring, the rest of the stuff Holley supplies is exotic or for racing. It's not an economy carb though - with a vacuum secondary, your driving style will make the most difference in fuel "economy."

 

yeah it seems to idle fine. The plugs look fine. Just when giving a little throttle it seems to hesitate. Also cannot tell if secondaries are coming on at all.
All I have messed with is getting floats right and mixture right.
Other than that nothing has been adjusted. Also it seems to die right when I come out of Park and into Gear. Lastly it will never start without giving it gas. Thats cold or warmed up. With my 2 g it seemed to run stronger..by this I mean it didnt want to die as easily as with the 390. If I went subidle the 2g would keep it alive. Now it just dies. Not sure what thats about. I just am posting everything that I have noticed......
Power wise, the holley is blowing the 2g away.