Hello, so i am trying to get my new carb dialed in, i have went from 65 primary jets to 67, I have also put the quick change cover for the secondary springs on. Holley says you should not have a "seat of the pants feeling" when the secondaries open, and by god thats what i have. I also am running the lightest spring for the secondaries, a 6.5 power valve. I know this carb. is undersize for my 360, but i am saving for a house so just trying to get the most out of it. I guess they say if you really feel the secondaries open its actually a power loss, and it should be a smooth transition all the way through, any thoughts?:angryfir::angryfir::angryfir::angryfir:
holley 4160 help. 600cfm.
- Thread starter chris17
- Start date
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hotstuff1
Well-Known Member
If its making good power and pulling hard ,I don't think you have a problem.
Bulldozer
free ice cream sandwiches
I don't understand the problem? and for comparison sake, 1969 440's dropped in the imperials came with a holley 600 as standard equipment. that carb is not too small for a 360 unless its "built", if anything ,its perfect
I have the same carb you have on my 440 now , I went from 64 to a 67, and its a perfect match. im at 5800 ft above sea level. there are a bunch of holley pump shot and other tuning videos on youtube
I have the same carb you have on my 440 now , I went from 64 to a 67, and its a perfect match. im at 5800 ft above sea level. there are a bunch of holley pump shot and other tuning videos on youtube
Not really a problem, just trying to better things. Like it seems to me even with the lightest spring for the secondaries they still open a bit late, like 3,300 to 3,500, i would like to be a little earlier. Also should i need to change the metering plates accordingly to primary jet changes. The car works great, just having fun trying to get more ya know.
Bulldozer
free ice cream sandwiches
I hear you there , im always playing with my carbs trying to get them perfect. I just picked up a carter afb 750 im going to replace the holley with just to see if its any better. if you haven't , check out some of the holley tuning videos. im still learning those things myself
Size: That's perfectly fine based on what you've described.
Kick: It's hard to know based on description. There's smooth kick and there hesitate and kick and all sorts of subtlies that I hesitate to diagnose whether its OK or not. But you can do some experimenting. Disconnect the secondaries. Then see what if anything changes. If it still kicks then its the trans kicking down or the PV at a bit too low of an opening point.
If you're really into it, then put it on the chassis dyno or at the drag strip run it on the primaries only. Get the best jetting. Then hook up the secondaries and jet them.
If the secondaries are opening too early, you'll be able to figure that out because it should hesitate or at least build less power until the rpms get higher. This is the advantage of a dyno - you get the datalogs of rpm and lamda (converted to AFR usually) as well as torque and power.
Basically what you have found matches what I have found. Secondaries come in around 3000 rpm, usually higher, on this size engine and carb. Exceptions would be purposely set up mech secondary carbs with 1:1 linkage for some race setups, etc.
Kick: It's hard to know based on description. There's smooth kick and there hesitate and kick and all sorts of subtlies that I hesitate to diagnose whether its OK or not. But you can do some experimenting. Disconnect the secondaries. Then see what if anything changes. If it still kicks then its the trans kicking down or the PV at a bit too low of an opening point.
If you're really into it, then put it on the chassis dyno or at the drag strip run it on the primaries only. Get the best jetting. Then hook up the secondaries and jet them.
If the secondaries are opening too early, you'll be able to figure that out because it should hesitate or at least build less power until the rpms get higher. This is the advantage of a dyno - you get the datalogs of rpm and lamda (converted to AFR usually) as well as torque and power.
Basically what you have found matches what I have found. Secondaries come in around 3000 rpm, usually higher, on this size engine and carb. Exceptions would be purposely set up mech secondary carbs with 1:1 linkage for some race setups, etc.
OldmanRick
Well-Known Member
I know you made some progress recently on this (from another thread) and I think your getting close.
I'm not convinced that the secondaries are open too late. As Mattax said, opening a little quick can give the same sensation also.
I believe you still have the tight converter and 2 series rear gear. Some of what your feeling may just be the "engine getting up on the cam" between the 2 to 4 grand transition area.
I'm not convinced that the secondaries are open too late. As Mattax said, opening a little quick can give the same sensation also.
I believe you still have the tight converter and 2 series rear gear. Some of what your feeling may just be the "engine getting up on the cam" between the 2 to 4 grand transition area.
Yes Rick, my vacuum is at 12-12.5 at idle, in drive. It does feel more balanced out on a 1/3 throttle take off now with the 8.5 power valve. Is this a typical result? Also could I go fatter on the jetting you think?
And finally, I have looked at purchasing the metering plate adapter for the rear so I could use standard jets, wondering if I should be making changes there since I have went from a 65 to a 68 on the primary? And I am running the lightest spring for the secondary actuation.
ramcharger
Dismember
If you feel lag when the secondaries open, that's due to the secondaries opening too soon and not having enough air velocity to pull fuel through the main nozzles. What you feel is the main nozzles "Crashing In" once the revs come up. Put in a heavier spring.
OldmanRick
Well-Known Member
Yes, the enrichment is now occurring with a little less throttle opening which is what I believe is needed in many circumstances.
As far as the plate or conversion and jetting, could you confirm which carb you have. I'm guessing it may be a 80450, 80457, etc. and not a 1850-? Could you give me the list number off the air horn.
green1
Well-Known Member
What is vacuum at idle? That dictates the power valve, stay 2 steps above that #. Then disconnect secondaries. Run it wide open, shut down, and read plugs (this eathonal makes it hard). Adjust jets. Hook up secondaries, at factory jet and spring.
Run hard, no feel? good. Shut down, no idle after that run, read plugs. Adjust jets. If the engine wants the secondaries, it opens them on it's own. Remember, a stock 340 or whatever, only needs 400 cfm. Cam, etc, will want a little more.
Don't bog it with secs oping early. slows you down.
Run hard, no feel? good. Shut down, no idle after that run, read plugs. Adjust jets. If the engine wants the secondaries, it opens them on it's own. Remember, a stock 340 or whatever, only needs 400 cfm. Cam, etc, will want a little more.
Don't bog it with secs oping early. slows you down.
The vacuum at idle in drive is right at 12, i went from a 6.5pv to a 8.5. Yes i think after work today i will try and tinker with a heavier secondary spring.
Hey Rick, i didnt get a chance to get back out to the shop last night, helping thhe kiddo with science fair project. Anyhow, i will get the numbers off the air horn around noonish and post. Thanks again.
Hello Rick, the list # off the air horn are as follows 80457-9
0532
Don't know if the bottom one means anything.
OldmanRick
Well-Known Member
Hey Chris, I wanted to check your plate specs. It's number 134-39. The "39" would be stamped on it.......Anyway, it has a jet orifice of .073. That's the equivalent of a #70 jet. Your still a little oversquare on the secd side so I don't think you need to jet up for that specific reason.
It's nice to have the convenience of a jetable plate or block, but I think i'd drive it a while and keep a occasional check on the plugs to see how there coloring. I'm not sure you'd gain alot, unless you hammering on it constantly......lol. I should add, make sure your float levels are just at the weeping point on the site holes.
I'd still play with the secd springs a little and see if you can detect any improvement.
Saetun
Sinister Swinger
If you've got a spare metering plate, it may be worth your while to drill out the plate to accept standard jets. not a tough mod but makes tuning a little easier. just thow #70 jets in as your baseline since you already know you came out of the box with that equivelant.
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