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Author Topic:   Holley Set-up
Flanndad
Dirt Full Roller

Total posts: 49
posted February 25, 2003 05:51 AM
I'm setting up a Holley 4779 750cfm (double pumper gas),
What would be a good starting point for the jets, and would you plug the power valve or what size would you use.
Car = Olds Cutlass 3,000 lbs, 406 chevy,
461 heads w/2.02 valves, 5.68 final drive,
Headers, Gm high rise marine intake, 1/2 mile fast track, 13 to 1 compression.

Flanndad
Dirt Full Roller

Total posts: 49
posted February 25, 2003 05:53 AM
Forgot cam info:
Intake 550
exhaust 560
Lobe seperation 106

outlawstock17
Dirt Forum Champ
Total posts: 620
posted February 25, 2003 09:06 AM
if i recall correctly, 4779's come from holley with 72 jets. that's where i would start. a healthy 406 might like a bigger jet. it takes about 2-3 jet sizes to make a noticeable difference, so i'd go up in 3's until the plugs looked good. weather also plays a role, cooler temps = bigger jets.

flanndad#17
Dirt Full Roller

Total posts: 28
posted March 06, 2003 05:39 PM
How does this sound?
75 jets in the primary side with a 6.5 power valve.
82 jets in the secondary with a power valve plugged.
Would this be a good place to start?

gahainsey
Dirt Full Roller

Total posts: 43
posted March 07, 2003 12:28 PM
Holley jetting depends on the 'dash' number of the carb and blocks. There are several different 'stock' jettings so a 73 could 2 sizes rich on one dash number and 3 sizes lean on another.

rico 08
Dirt Freak

Total posts: 372
posted March 07, 2003 09:45 PM
A 75 on front may make it load up on idle(mine did)i'd use a 71-72 on front with a 83-86 on rear IMHO

66jj
Dirt Freak

Total posts: 352
posted March 07, 2003 10:37 PM
block the power valve and start at 8 over stock on the front, and stock in rear.

call a speed shop to find out stock jetting for your carb, dont tell them any - #s as those are for specific applications. i have the stock jetting written down on my jet kit, but its in storage or id look it up for you.

if i remember i started at 77-82 with power valve blocked.

also if its going on a open plenum intake make sure to remove the center ***** holding on the baseplate, it will fall out if theres nothing under it, guaranteed!!!!!!!!!!!

jeff

flanndad#17
Dirt Full Roller

Total posts: 28
posted March 08, 2003 10:27 AM
66jj, you mention blocking the front power valve. In a Holley book i have, it say's with the front blocked off you will probally foul the plugs if you let it idle much.
In the book i have it also say's to up the jet's 8 to 10 sizes when you block it off, maybe on the front if I keep it close to stock at the 72 jet it wouldn't foul.
So I wasn't sure if I should block the front or not.
Anyone tried this and did you have any trouble?

autoshop
Dirt Maniac

Total posts: 102
posted March 08, 2003 10:50 AM
I ran 80's front and back , When i ran gas...

66jj
Dirt Freak

Total posts: 352
posted March 08, 2003 11:28 AM
ive blocked the front for years, you need to start up say 8 jets, and adjust from there. if you dont go up it will be lean.

i never had a problem fouling any plugs, once you get the jetting right it will be fine.

if your really worried start 6 higher in front and your going to be checking the plugs at the track right away anyhow.

i have never ran with a power valve so i cant say its better plugged, but to me its one less thing that can go wrong, and it removes one variable, since the power vavle works of vacumn it should be more consistent with it blocked..

also all i know is i have seen dozens of guys looking for power valves at the track, and have never had to look for one!!!

jeff

flanndad#17
Dirt Full Roller

Total posts: 28
posted March 08, 2003 05:58 PM
From these discussion's and other's by word of mouth, it look's like i'll start with two power valve plugs and 80 size jet's front and rear.
And let's see how the plug's look.

One more question, when you take off the choke linkage what has been the item of choice for filling in the hole's to keep the dirt out. KB weld or what?

66jj
Dirt Freak

Total posts: 352
posted March 08, 2003 07:21 PM
only hole you need to fill is the one the rod goes thru. i use jb weld so its done forever...

jj

80-80 will be a lot, but you can back up easily.

from your cam specs lift tells us nothing, we need your at 50 degrees duration, if its the 256/264 cam or close that thing pulls hard in a 383 or 406...

superdave
Dirt Forum Racer

Total posts: 89
posted March 08, 2003 10:17 PM
If the plugs look good after a race but the engine loads up on idle and you have the power valve plugged then the throttle is open to far and pulling fuel from the transfer slot. Crack the secondary butterflies open a little to let some air in and close the fronts a little. Many people and carb builders drill a small hole in the primary butterflies to accomplish this same thing.

Good luck,

------------------
Superdave
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66jj
Dirt Freak

Total posts: 352
posted March 08, 2003 10:50 PM
good pt superdave.

he should just drill the holes, i allways have, i just thought everyone did.

jj

flanndad#17
Dirt Full Roller

Total posts: 28
posted March 09, 2003 04:24 PM
Duration At .050
259/Intake
262/Exhaust

I did read about drilling a hole in the primary's I'll have to look it up to see what size. It seems like 3/32 but i'm not sure.

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