4160 Carbs

[shaun]

I have 2 Holley 660 carbs, the 4160's. I tore one down last night to do a rebuild on them and have a few questions for you carb guys.
First off i read thru a holley rebuild manual i have and it talks about how one can convert a 4160 to a 4150. They basically say the only reason to do this is for those guys who want to fine tune the carb. Is this worth doing, i'm not tryign to set any records but if it's a good bank for my buck then might as well.
Second i couldnt find any power valves, this is really my first time tearing into a carb like this so i'm not even sure what i'm looking for but according to the book some people take the power valves out. It says that if you do this to jet up 6-8 sizes. Should i put a power valve in it? The rebuild kits i have dont look like they have them.
Also, the book talks about the stock/standard jet size being 50... We'll i have 70's in this carb (havnt tore the other down yet). I know people jet up when they increase performance and all but 20 sizes to me seams like a big increase, but then again i dont really know if 20 sizes up is all that big.
Also, theirs a flat plate on the side of the carb that doesnt have a metering block, it was stuck on their and even though i used a flat gasket scraper like tool to get it off it's not perfectly flat anymore. Does that matter?
So far i have most of the parts sitting in chem dip, these carbs have been sitting probably 8 years...

[058]

Assuming you have the 660 center squirter [list no. 4224] the main jet should be 76s with no power valves in the pri. or sec. Converting to a 4150 just means adding a secondary metering block so that you have changeable jets. Holley sells kits to do this and about the only thing you need to concern yourself with is the Idle Feed Restriction [IFR] of the sec metering block. The metering plate the carb should have will be stamped "12" and should have a .076" main feed and a .031" IFR. Your main jetting should start close to what the plate has.

[steelcomp]

Sean,
Thise carbs are built for one thing, and one thing only, and that's wide open throttle. They don't come with power valves, and you'd have to change the primary metering blocks to intstall them. The secondary's have the metering plates, which have the idle and high speed circuits in them, with no adjustable jetting. If you plan on doing any cruising with these carbs, I'd get the kits for the conversion. The stock jetting for your carbs are 76's in the primaries, and a #12 plate in the secondaries, with a 25 squirter nozzle. I really don't like these carbs for anything but all out racing, but there's lots of guys that seem to put up with them. If it were me, I'd sell 'em, and get a pair of plain 4777 650 DP's, or similar. I think you have to do too much work to these to make them "user friendly", when there's better carbs out there, but I understand you have them already, and probably want to make them work.
Sorry for the repeat of details...058 beat me to it. :D

[GofastRacer]

Sean,
Thise carbs are built for one thing, and one thing only, and that's wide open throttle. They don't come with power valves, and you'd have to change the primary metering blocks to intstall them. The secondary's have the metering plates, which have the idle and high speed circuits in them, with no adjustable jetting. If you plan on doing any cruising with these carbs, I'd get the kits for the conversion. The stock jetting for your carbs are 76's in the primaries, and a #12 plate in the secondaries, with a 25 squirter nozzle. I really don't like these carbs for anything but all out racing, but there's lots of guys that seem to put up with them. If it were me, I'd sell 'em, and get a pair of plain 4777 650 DP's, or similar. I think you have to do too much work to these to make them "user friendly", when there's better carbs out there, but I understand you have them already, and probably want to make them work.
Sorry for the repeat of details...058 beat me to it. :D
Well sheezz I have to disagree with ya on this one, LOL... When I had a MAJOR brain fart and ran carbs, I used 4224's and they worked flawlessly in any condition. And all I did was convert to center hung float bowls and put a metering block on the secondaries and ran them sideways. They would idle at 800 all day long and I could cruise at 2500 all day long without a stumble or loading up, then stand on it and go!.. BTW, quick cam specs were 669/648 lift, 268/272 @ .050!.. In my worthless opinion 660's are a good tunnelram carb!.. :D
http://www.hotboatpics.com/pics/data/500/21Image004.jpg

[steelcomp]

Well sheezz I have to disagree with ya on this one, LOL... When I had a MAJOR brain fart and ran carbs, I used 4224's and they worked flawlessly in any condition. And all I did was convert to center hung float bowls and put a metering block on the secondaries and ran them sideways. They would idle at 800 all day long and I could cruise at 2500 all day long without a stumble or loading up, then stand on it and go!.. BTW, quick cam specs were 669/648 lift, 268/272 @ .050!.. In my worthless opinion 660's are a good tunnelram carb!.. :D
http://www.hotboatpics.com/pics/data/500/21Image004.jpg
That's "all" you had to do with them?? :confused: :D
Like I said, some guys had good luck with them. :coffeycup

[shaun]

We ran these carbs on the 396 that was in the boat when my parents had it for years, and we did most of our cruzzing at 3000 to 3500 RPM and the boat ran ok, i dont remember any loading up or stumbling... These are sitting on a tunnel ram.
I think for now i'll leave them the way they are and when i finally get the boat back together and out a few times we'll see how they do.
As for that plat not being perfectly flat is that going to be a problem? I'm not talking about the 1/4" thick plate that the screws go into, that sits ontop of this.
Also, you said 76's are stock, this has 70's in them with a 396, but now the motor is a 468, 10ish comp with a cam from chris straub (dont have the specs yet).
hey stealcomp it's shaun :D

[GofastRacer]

That's "all" you had to do with them?? :confused: :D
Like I said, some guys had good luck with them. :coffeycup
Forgot to mention, I did have to enlarge the shooter a bit!.. :smile:

[GofastRacer]

Assuming you have the 660 center squirter [list no. 4224] the main jet should be 76s with no power valves in the pri. or sec. Converting to a 4150 just means adding a secondary metering block so that you have changeable jets. Holley sells kits to do this and about the only thing you need to concern yourself with is the Idle Feed Restriction [IFR] of the sec metering block. The metering plate the carb should have will be stamped "12" and should have a .076" main feed and a .031" IFR. Your main jetting should start close to what the plate has.
According to Holley, a #12 plate equivilant is a 73 jet!.. ;)

[steelcomp]

We ran these carbs on the 396 that was in the boat when my parents had it for years, and we did most of our cruzzing at 3000 to 3500 RPM and the boat ran ok, i dont remember any loading up or stumbling... These are sitting on a tunnel ram.
I think for now i'll leave them the way they are and when i finally get the boat back together and out a few times we'll see how they do.
As for that plat not being perfectly flat is that going to be a problem? I'm not talking about the 1/4" thick plate that the screws go into, that sits ontop of this.
Also, you said 76's are stock, this has 70's in them with a 396, but now the motor is a 468, 10ish comp with a cam from chris straub (dont have the specs yet).
hey stealcomp it's shaun :D
Hey Dude...how's the project?
For the 468 I'd bump up to the stock jetting and go from there. That little plate has been eliminated on later model 4160's. If you're running the blue gaskets, just screw the secondary metering plate right over the gasket.
Keep us posted.

[GofastRacer]

I ran stock jets in my 468 and the only time I had to rejet was if the air really came in crisp and dry then I'd have to fatten it up one size!..

[great_escape]

I run 660's on a 496 with 10.25:1 comp. And I love them now. Some work involved. I changed over to center hung float bowls a 4150 conversion kit and larger squirters. The motor has a large solid roller And likes 73 jets for the pri and 74's sec. The motor idles at about 900 and is very crisp, no stumble here.

[shaun]

Hey Dude...how's the project?
For the 468 I'd bump up to the stock jetting and go from there. That little plate has been eliminated on later model 4160's. If you're running the blue gaskets, just screw the secondary metering plate right over the gasket.
Keep us posted.
It's comming along, more expensive than i though it was going to be :) but isnt that always the case...
The rebuild kits i have are probably 10 years old, they where never opened, still plastic wrapped but i'm wondering if i should purchase new kits... The gaskets are all black and this kit is called the holley renew kit if i recall correctly.
I'll bump the jets up to stock to start.

[058]

It's comming along, more expensive than i though it was going to be :) but isnt that always the case...
The rebuild kits i have are probably 10 years old, they where never opened, still plastic wrapped but i'm wondering if i should purchase new kits... The gaskets are all black and this kit is called the holley renew kit if i recall correctly.
I'll bump the jets up to stock to start.Get new kits. The black gaskets have probablly shrunk, with the new kits you will be getting the latest style gaskets and if you were running power valves you would be getting the so called "blowproof" P/Vs....if there ever was such a thing. :rolleyes: