holley jet number?

[Johnny Blaze]

I pulled the holley off my truck for a quick rebuild.

I noticed the numbers on the jets seemed odd.

It is either 582 with the 2 being upside down
or 285 with the 5 being upside down.

The numbers are all together and no other numbers on them.


What jets are these?

The truck runs lean by the way.

[Shaker455]

Those are called Closed Limit Jets and they are supposed to be more accurite than a standard two number jet.

If your running lean you can jet it up to a standard size jet and there may be a chart to see where you are on the jet scale.

[MonzaRacer]

Which carb number and just for the question whats the number stamped on power valve, and what engine in truck? mods?
If its a 600 holley you could jump up to say a stock 1850 jet of 64 or 66 or simply keep adding jet size till it starts darkening up the plugs a touch. Also you may need to do some advancing of timing, moving vac advance to manifold if not there already.
582 is kind of lean for a truck. Most tuners will jump 2 sizes ie 58 to 60 to 62 then you can lean back one then if it needs better clean up go to close limit jet. But IF I remember correctly the close limits are set to with in 1% where std jets are like 4 % variance.

[Johnny Blaze]

carb is a 9776 model.

Had a 4.5 power valve, changed it to a 7.5

vac advance is at ported vac source. No pinging, set at 10deg.

Motor is a 250 with clifford intake and headers.

[MonzaRacer]

Try upping to about a 62 jet maybe 63.
Move vacuum advance to manifold vacuum, but before you do giver a jump to about 14-16 initial then manifold and then readjust idle back down and see if it likes it. if it rattles drop back 2 sizes at a time. but I would say with the headers and intake it could probably use even larger but 62-63 would help a lot.
Good luck.
Or you can keep adding 2 degrees till it pings then back down. But use the vacuum advance in manifold, it will make a difference.
and make sure centrifugal advance is operating might even look for advance kit and get some lighter springs if your into it.

[Johnny Blaze]

I left it at 10 degrees based on the famous inline six books recomendations.
He also stated ported vacume for a sreet set up, as most others have stated also.

The dist. Is a brand new custom built HEI Unit.