600 holley jet size starters? [Archive] - Chevelle Tech

: 600 holley jet size starters?


66dream
Mar 18th, 08, 8:35 PM
I have a 355 with 600 Holley, headers, 5 speed, 226 duration cam.
1)What size main jets should I start out with?
2) Also any help figuring out how to tell whats the best jet for this set up (ball park) would be appreciated.
p.s. I should have a air fuel ratio gage comming soon that I purchased from graigs list.

SWHEATON
Mar 18th, 08, 9:30 PM
With that cam in a perf 355 with headers 70-71 prim jets for 1st try which should be fairly close to where it needs to be,should only need a slight tweak from there at most.

BTW,since your obviously dialing in the tune of the motor what base & total tiuming are you currently running?

With that cam you need approx 18 deg base & 18 deg mech in dist all in by 2800-3k rpm.

Then 18 base + 18 mech in dist = 36 total.

You also need a vac adv for street use.

Scott

Dave427
Mar 18th, 08, 9:39 PM
Stock jets for a Holley 600 Vacuum secondaries is 65. I would go no bigger than 68's.

Dave

66dream
Mar 19th, 08, 11:19 PM
My notes from when I last had the carb apart say main jets are stamped 601.
Does anyone know how this would relate to 65 or 68 jets?


Stock jets for a Holley 600 Vacuum secondaries is 65. I would go no bigger than 68's.

Dave

Dave427
Mar 20th, 08, 12:11 AM
Correction stock jets are 66. Going to 68 is a good start.

Dave

Tom Mobley
Mar 20th, 08, 2:53 AM
I've got an idea: Why don't you install the right jets which would be 64, then if the meter says you need changes start from there.

If it really had 601 it's probably not a 600. I would expect your carb to have 642s if it's fairly recent.

if the jet numbers have 3 digits with the last number being an upside-down 2 then you have close tolerance jets. These are pretty common in recent Holleys or emissions type Holleys.

Can you post the LIST number from the front of the choke horn?

66dream
Mar 20th, 08, 8:41 AM
The list number is 1850-3
I think this carb has jets from other than original for sure. the reason they say 601 on them.

SWHEATON
Mar 20th, 08, 9:46 AM
68-70 is a good starting spot but remember this is not a stock 350,its running a perf cam,perf intake,headers which can usually use a little more fuel calibration in the setup .

Thats why i suggested 70 for a start but 68 is ok,maybe slightly lean but ok,can always go up a tick if needed.

Scott

SWHEATON
Mar 20th, 08, 9:50 AM
66DREAM,did you choose that site name becasue you have or had a 66 HONDA DREAM,my father had a black 66 305 Honda Dream in 1969-70 time frame.

68-70 is a good starting spot but remember this is not a stock 350,its running a perf cam,perf intake,headers which can usually use a little more fuel calibration in the setup .

Thats why i suggested 70 for a start because 68 is for a basically stock motor but is ok for a start,maybe slightly lean but ok,can always go up a tick if needed.

Scott

66dream
Mar 20th, 08, 2:29 PM
My site name is because my kids have been telling me for 14 years that my car will never be done.

Just pulled my jets they are not 601 they look like 602 with the 2 (last digit) upside down and small looking around .055 inch diameter.
You guys are saying start out with 65-68. The problem I'm having is rich smell when driving and black shoot on rear bumper above tail pipes. (Will the larger jets ie: 65-68 help with the richness or make it worse?)
I purchased a air/fuel ratio gage on graigs list but the guy says he never got the bank draft.
What to do..............put old jets back in or try larger diameter (65-68) jets?
thanks in adbvance!
66DREAM,did you choose that site name becasue you have or had a 66 HONDA DREAM,my father had a black 66 305 Honda Dream in 1969-70 time frame.

68-70 is a good starting spot but remember this is not a stock 350,its running a perf cam,perf intake,headers which can usually use a little more fuel calibration in the setup .

Thats why i suggested 70 for a start because 68 is for a basically stock motor but is ok for a start,maybe slightly lean but ok,can always go up a tick if needed.

Scott

SWHEATON
Mar 20th, 08, 4:49 PM
65,66 is too lean for a perf 350 with perf cam,perf intake,along with headers so start with 68 and then dial in (up or down)the fuel calibration better from there if required.

But dont forget to get the timing curve correct 1st,thats the correct way /sequence to go about it.

Scott

onovakind67
Mar 20th, 08, 4:56 PM
I'd start with a stock 66 jet and drive it.

66dream
Mar 20th, 08, 7:42 PM
ok, I put the 67 main jets in, dont have the air/fuel gage yet, but still stinky (gassy smell) at idle and cruise from tail pipes
I have been down the timming route and have it set as youv'e suggested from months ago.
Still this stinky Holley!:angry:
1850 600 Holley
vac secoundary with a metering plate and in rear .
My floats are adjusted with just a drible out the sight bolws when car is shacken,
4.5 power valve
about 8lbs fuel pressure
about 10 inches of vacume at idle
67 main jets
.033 IFRs' with .005 wire in
No noticable drible from boosters when idle, but very rich at idle.

Do you think I need to go smaller yet with the IFR's?

Jebchevelle
Mar 20th, 08, 8:01 PM
ok, I put the 67 main jets in, dont have the air/fuel gage yet, but still stinky (gassy smell) at idle and cruise from tail pipes
I have been down the timming route and have it set as youv'e suggested from months ago.
Still this stinky Holley!:angry:
1850 600 Holley
vac secoundary with a metering plate and in rear .
My floats are adjusted with just a drible out the sight bolws when car is shacken,
4.5 power valve
about 8lbs fuel pressure
about 10 inches of vacume at idle
67 main jets
.033 IFRs' with .005 wire in
No noticable drible from boosters when idle, but very rich at idle.

Do you think I need to go smaller yet with the IFR's?

Have you put a vacume gage on this motor to see what it is at idle and under throttle I ask be cause I noticed the 4.5PV if the pv opens to soon the car will run rich and have a gas smell. my next question witch may help to answer some tunning questions is are you running a open plane or dual plane intake also what brand. will need more info to give you a real world answer like what cam are the exact cam spects, comp ratio and the above mentioned intake info as well as vac readings. Jeff

66dream
Mar 20th, 08, 8:41 PM
Dual plane intake, Eldelbrock RPM,compression ratio 10:1
I will have to try the vaccum while driving later tonight or tomorrow
Here is specs on my cam :

66dream
Mar 20th, 08, 8:49 PM
resized the scan from cam specs.
hope this helps

Jebchevelle
Mar 20th, 08, 9:06 PM
Dual plane intake, Eldelbrock RPM,compression ratio 10:1
I will have to try the vaccum while driving later tonight or tomorrow
Here is specs on my cam :

OK what was vac at idle and are you useing 1.6 or 1.5 rocker arms and or both like 1.5 on intake and 1.6 on ex. or other way around. thanksfor the info so far.

66dream
Mar 20th, 08, 9:13 PM
1.5 rockers on both intake & ex.
vac at idle is right around 10

Jebchevelle
Mar 20th, 08, 9:19 PM
ok let me know what the cruise vac is right now looks like to small pv for starters I would put a 5.5 or 6.5 in it then start tuning but need to know the other vac rateing to know witch one to use.

66dream
Mar 20th, 08, 9:35 PM
I'll try the cruise vac tomorrow and let you know. It's dark and I need to get more gas before I test.
Just a curious question though: Maybe I have it mixed up but,
I always thought that the power valve with a lower number would open later and not sooner (or stay shut longer)
Maybe I'm all wet. I will definitly let you know what I find out tomorrow.
Thanks for the help thus far!

Tom Mobley
Mar 20th, 08, 9:38 PM
Let's see, you're complaining about rich, but you've installed 67 jets which are at least 3 sizes too big. What's wrong with this picture?

CARBURETOR #
PRIMARY METERING JET
SECONDARY METERING PLATE
PUMP DISCHARGE NOZZLE
PRIMARY POWER VALVE
SECONDARY DIAPHRAGM SPRING
0-80457S
********
64
********
39 PLATE*
0.031
65 PV
Black


0-1850C
*********
64
********
39 PLATE*
0.031
65 PV
Black


0-1850S
********
64
*******
39 PLATE*
0.031
65 PV
Black

Tom Mobley
Mar 20th, 08, 9:39 PM
the 39 secondary plate is equivalent to a 70 jet per the Holley site, where this stuff is easy to look up.

Jebchevelle
Mar 20th, 08, 9:51 PM
yes it is thanks for chiming in Tom others here told him to go to the bigger jets I was trying to get him back or at least close to original specs and then go from there.

Jebchevelle
Mar 20th, 08, 9:53 PM
and it was m understanding may be wrong but if you have ten on vac and go to a 4.5 doesnt it open sooner I may have to look cause I may have it backward in my head? hence why I like eddy's less crap to deal with. lol

66dream
Mar 20th, 08, 10:09 PM
I was running these to begin with.
602 with the 2 (last digit) upside down and small looking around .055 inch
Now with the 67 jet, strangly enough it really didn't seem to make much difference.




diameteryes it is thanks for chiming in Tom others here told him to go to the bigger jets I was trying to get him back or at least close to original specs and then go from there.

Jebchevelle
Mar 20th, 08, 10:16 PM
I was running these to begin with.
602 with the 2 (last digit) upside down and small looking around .055 inch
Now with the 67 jet, strangly enough it really didn't seem to make much difference.




diameter

Thats what made me suspect pv no change after chaining jets. I need to do some looking I always screw up with holleys on the first try lol but I get it right eventually:p no but in all honesty I need to see what holley rates your 602 upside down jet at so I can figure out where you need to go from that size. also I need to know what plate you might have to change to all this info is on the holley site so I will brb.

Jebchevelle
Mar 20th, 08, 10:31 PM
ok here it is Tom answered the jet question thank you Tom. if I were you I would put the original jets back in set everything up like the carb was stock with a 6.5 PV and the 602 jets then run it and see what it does if it is still rich I would check the float levels one more time and no gas should come out of the opening I just reread some of this if you couldnt tell and i set the floats so the gas is just about to come out but dont. next a question I overlooked asking how long has the carb been on the car and did it always do this? also have you watched the carb with the air cleaner off to see if gas is dripping or leaking into the system? I know some of the questions and steps are repeats but it is how I think things get solved.

baddbob71
Mar 20th, 08, 10:56 PM
I would think that cam should pull 12-14" of vacume at idle being only 224@.050
The power valve has no effect on idle richness unless it is ruptured and leaking.
A 4.5 power valve will open if and when the vacume drops to 4.5 or below and will add fuel to the main jet circuit through the boosters-nothing at idle or part throttle cruize.
I would start at the factory jet recomendation and I think most 1850's come with 65 on the primary side. Tune your idle circuit first before messing with jet selection, power valve, pump shot, and secondary spring.
Usually a rich idle is caused by too much throttle opening where fuel is flowing out of the transition slot when it shouldn't be. Where are the throttle blades set at? How much of the slot can you see? How many turns out on the mixture screws now?

66dream
Mar 20th, 08, 11:18 PM
only about .020 of transfer slot showing.
idle muixture screws at 1.25 turns out from seated

66dream
Mar 21st, 08, 10:09 AM
Yes every Holley I have ever had has been stinky rich. (dont know why)
I will readjust my floats (do you think 8lbs fuel pressure is too much?)
Also in above post the mixture screws are 1.25 out from seated. still rich......:confused:


ok here it is Tom answered the jet question thank you Tom. if I were you I would put the original jets back in set everything up like the carb was stock with a 6.5 PV and the 602 jets then run it and see what it does if it is still rich I would check the float levels one more time and no gas should come out of the opening I just reread some of this if you couldnt tell and i set the floats so the gas is just about to come out but dont. next a question I overlooked asking how long has the carb been on the car and did it always do this? also have you watched the carb with the air cleaner off to see if gas is dripping or leaking into the system? I know some of the questions and steps are repeats but it is how I think things get solved.

66dream
Mar 21st, 08, 1:31 PM
I just checked vacuum is actulally running at 15 at idle and about 20 cruising down the road.
re checked & the floats are set

Yes every Holley I have ever had has been stinky rich. (dont know why)
I will readjust my floats (do you think 8lbs fuel pressure is too much?)
Also in above post the mixture screws are 1.25 out from seated. still rich......:confused:

66dream
Mar 21st, 08, 10:56 PM
I guess everyone has given up on this one ha?

Tom Mobley
Mar 22nd, 08, 2:45 AM
did you ever get around to putting the right jets in it? I don't see where you posted that.

Jebchevelle
Mar 22nd, 08, 2:48 AM
no I backed out for awhile to let the know it alls do what they want if you are ready for some real tuning help drop me a pm. I am not the smartest or the best wont lie but I manged to make a 600 cfm holley two peice run 12:73 on an open plane intake on a 468 BBC with a 554 cam so I must be doing somethings right.