CarburetorsCarb discussion and questions. Upgrading a Third Gen carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
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i am going to try to rejet a new holley 4160 carb. i havent ordered jets, so my question would be if there are any extra parts to order to swap out a set of jets. i also was wondering if anyone had any tips on doing this because i have not torn down a carb before.
Something's screwy- 4160s aren't machanical secondaries. They're vacuum secondaries. I know that carb and all the specs look right except the part about mechanical secondaries. Don't think so. Never seen one like that with mechanical secondaries.
Anyway.... 4160s only have jets on the primary side of the carb. The secondary side uses a metering plate, which has fixed jet orifices drilled into it (you can change plates to alter jet size, but otherwise the secondary side is "non-adjustable")
Anywho...... float bowl gasket is the only thing you should need when doing a jet change. When you pop off the primary bowl you'll likely rip the bowl-to-metering block gasket, which will require it's replacement. The o-ring on the fuel tube between the primary and secondary bowls is reusable, and that's about all you need to touch for a simple jet change.
Secondary side, assuming you're going to change metering plates, is basically the same deal, except that the bowl and the metering plate both seal against the same gasket (a secondary metering block gasket, even though the carb does not have a metering block on the secondary side- it uses the same gasket there).
For gasket information about the primary and secondary side of your carb (and a ton more info) there's a very useful PDF on Holley's website:
do you know what size the secondary metering plates are? and if i go down 2 sizes in primaries, how many "sizes" should i go down with the secondaries?
at no point will i ever say you are wrong about anything but i swear that my carbs have mechanical secondaries. here is the link for them. thanks for the imput.
65/70 are the jets / metter plate sizes on all 4160 carbs (at least that is what the holley manual you got with the carb should have told you if you bought it from a store). You can do a 4150 upgrade to them so you have the jets in the rear too. You can also get the fuel bowl upgrade that will allow you to change the jets without removal of the fuel bowl. Pretty simple either way really.. you will just need a gasket (and depending on the ones you get for it some are reusable some are not.) the little o-ring mentioned above is reusable. and since it is new you should not have any problems really. after a year or two though they get really soft and tend to tear when trying to put them back in. I am in the process of a full rebuild on one. got it basically free on top of a new performer intake. mine is the 650cfm one however. and all 4160's are VAC secondaries. At any rate 150$ for my new performer/used holley works for me.. i can put 50 to 100 into the carb and still come out ahead lol.
possibly.. but when i opened up the box it did not even list a 450cfm 4160... so it could well have smaller... do you know the product number on the carb? And did you buy it brand new or used?
ok. now it makes more sense.. they converted a 4160 into mech secondaries and removed everything off the passnger side of the carb... that is the first mech sec 4160 i have every seen.. and likely to ever see again.... most people would run the vac sec 4160.... really that carb is not even in the same class as the other 4160's that were listed in the 4160's box i got... that one was not even remotely mentioned lol.. I can not imagine what all you will have to do with it to get it to work properly.. although if you have an auto you will need to get the throttle cable/tv cable braket, and the thing that goes onto the carb for the tv cable. else you will lose your trans in a hurry... the jets in it i have no idea. but you can easily tell. I used a flat tip screwdriver and just turned them out.. put the others back in the same way. no problems. and it did not leave a mark on the jets.. the jet size of the jets will be stamped on the side of the jet.. after that i think 5 jet sizes larger for the rear would probably be right for the plate size i think.
thanks for the info...you can remove them with out taking apart the bowls? plus im running a dual carb setup so i need to jo just a bit more lean for my car
oh.. noooooow it makes so much more sense.... yes there is a fuel bowl conversion you can get that will work on the 4160 carbs.. basically it replaces the bowl with one that has two plugs in it over the jets.. You remove the two plugs. let the fuel drain, and then use the jetting tool to pull the jets out and put them in, then screw the plugs back in. Now that i see the setup, i understand why the carbs are as they are... they are not really your normal run of the mill every day ones..at least for application wise. Summit sells the conversion.
sweet i was looking at that conversion but wasnt sure if that was something i would need...because ill need 2 of them. should i worry about the secondary metering plates? i t runs great, but a little rich right now. i was thinking a change of jets and a ignition box would fix it all
yea the plates you probably do not need.. the jets in the front would work.. the one thing about it though.. with your setup. that conversion will only work on the front carb, since the front carb blocks the second carb you would have to remove it either way in order to change the jets.... the secondary plates i would think would be ok, since those do not open up anywhat unless you are getting on it....
ahhh didnt think of that...ill just not get the bowls and just get everything else. im thinking that im about to get real good at working on a holley because i have a tunnel ram
oh yes lol.. one thing you should really invest in is the holley carb tune/rebuild/modification book... tells you everything you will ever need to know to get these things to work like that actually should.. and then better.
sweet...when i do change the jets out, is going down "2 sizes" a considerable amount? i was just going to try and replace the 58's with 54's and try it from there but i was thinking since i have 2 carbs maybe it would be like changing only "1 size" on a single carb. do i have this backwards?
what exactly is the difference between a 4150 and a 4160? they seem to always be grouped the same when buying items for them. and would changing the boosters give me better performance, that is if i can on a 4160?
the basic difference and most noticeable is the 4 corner idle control on the 4150 there is no metering plate for it.. basically the conversion package for the 4160 to 4150 gives you new fuel bows, new plates.. (i think it is only the back plate do not have the atalog in front of me) and basically gives you jet in the back instead of a metering plate. and then gives you another set of needles to adjust the back fuel flow. (like the needles on the front) Other than that.. i do not think anything else is really different other than the 4150 may not have a choke or choke horn. but the body and throttle plate are the same.. which is why they are normally lumped together.
i dont think i can make my carbs any longer than they are already, im just trying to tune a dual carb setup the right way lol if im even doing it the right way
yea with yours i do not think it would work.. and Mine came with the secondary idle adjustment.. perhaps two different conversions.. but yes.. the steal tube that is used to fill both bowls would need to be longer, or you chould run a different fuel line (a fuel line to each bowl via a spliter i think it is.. or something like a spliter)
from what ive read so far, i dont think i can replace the venturi boosters on my carb. 
