Posted By: wings471
/6 Holley 390 jets - 05/05/11 06:19 PM
I have a clifford intake/holley 390cfm on my /6. Only other upgrade is headers. Street driven, hiway geared, 3 spd. w/od. (4 spd).
What jets are you guys using in your 390 ? I think I need to go down 2-3 sizes as mine is running rich and would like a base to work from. Appreciate the help.
Posted By: jbc426
Re: /6 Holley 390 jets - 05/05/11 06:50 PM
The best way is to read your plugs or get a data logging wide band. FAST has a nice one for just over $400. It's portable so you can do a bunch of cars.
Here's a good page on plug reading on FBO's website.
http://www.4secondsflat.com/Spark_plug_reading.htmlMake sure your float level is set correctly. Also, did you shorten up the mechanical advance slots in the distributor? Slanty's like significantly more initial, but not more total ignition advance. The difference the distributor recurving makes in a slant is unbelievable. Are you still running points?
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Posted By: Dodgem
Re: /6 Holley 390 jets - 05/05/11 08:20 PM
stock is the best staring point found this
R6299-1 4160 390 37-1539 37-933 6-506 122-50 34R9716-34 N/S N/S N/A 0.025
so if this it it 50's front and 34R9716-34 plate
another could be the old power valve is pooched
R6895 4150 390 37-1536 37-933 6-504 122-50 122-62 N/S N/S 125-85 0.025
Posted By: Pyper70
Re: /6 Holley 390 jets - 05/05/11 08:30 PM
I added a second metering block kit (I believe its a gasket, fuel lines, power valve, jets, longer screws and the metering plate. I wanted better adjustment procedures out of it. I think I put a power valve block off in the secondary circuit. Its been a long while. My biggest concern for the slant and the 390 was the bog...I fiddled around with the primary cam, accelerator pump excessively...never could get rid of it...Start with stock jets and move up from there.