buick 350 with holley 600 (4160) jetting help

hey guys I got my buick 350 in my regal and runs good but hard starting when the engine is warm and it smokes a little during an Idle. the car has a stock 4 barrel intake modified, headers, cam lunati 275/285,.030 pistons etc. and running used 600 holley with a basic holley rebuild kit. So, the car is running rich from what i got, but does anyone have recommended jets the would run. Oh, almost forgot, the guy I bought the carb from said the carb came from a 351 ford, but he also said it was 650 cfm, but I checked numbers twice and it came up as a 600cfm. i was thinking on calling holley to see if they could tell me the jets to run or where to start. any help would be great. thanks Josh

 

I would not spend any money on a carb which is too small. For 50 bucks I could send you a 750 cfm Q jet for a Buick 350. 750 cfm is the correct size for your engine.

 

I would think 600 is plunty enough considering TA performance offers a kit for the 350 and 600 is whats included heres the link http://www.taperformance.com/proddetail.asp?prod=TA_1235P and holleys carb selector includes the 600 as option. BUT, A guy I worked with had bought a 750 Q-jet and used it very little. I'll try checking into that, it was on a olds 350

 

We know TA sells lots of 600 CFM carbs and TA intakes for the 350 however you would surprised to know that the TA intake is not worth any power gain and the carb is a HUGE downgrade from stock. We have dyno and track proof that the 350 loves a 750-1000 CFM depending on the other upgrades. Even most stock 350s swallow up a 850 holley without any issues.

Also if you care AT ALL about fuel mileage then swap to a Q jet as they are the best carbs for fuel mileage.

Also never use a carb from another size or brand of engine unless you are interested in completely modifying the insides of the carb. These carbs were custom built for the Buick 350 so use that carb on your engine or expect issues.

 

100% agree with the need for a Buick Qjet, or larger Holley if you refuse to go to a Qjet.

But, to answer your question on Jets, you already have a baseline in your carb. See what jets you have, and to smaller if it is rich. You need to learn that all 350 range cubic inches are not the same. 600 would work for a chevy, maybe ford too, but NOT for a Buick. Search and read on this forum. Many explanations why Buicks need more air flow, by their design.

 

And yes it is frusterating for everyone when people join V8 Buick after buying a 600 CFM carb, and then they learn from us it was a mistake...

 

well, i'm looking at a holley 750 if its what i'm looking for, I may get it, I'll just have to switch the electric choke from my 600 to it. the guy has $175 on it and it's only been used 6 months and it comes with an edelbrock air cleaner setup, he said he switched out the carb to a 750 holley double pump with mech. secondaries and later sold the car.and he said he never pulled it apart and that he bought new. so if I do get this what do you guys think for jetting. the carb #3310-11 which comes up as a 750cfm, and a 4160 model. don't know if this means anything but it has duel inlet on the choke side

 

well, i got it, any ideas for jetting?? seems like it runs better with the 750,but after start up when it's warm it wants to stall when i put in gear unless i give it gas, and after running alittle bit it comes out of it. maybe it loads up on idle? I have the fuel screws I believe 1 turn out.

 

There is nothing wrong with a 600 holley... period....personally , I would not trade just 1 for a whole truck load of qjet's....:Brow: i have one 600 that has been on a 401 and a 425 nailhead and it ran super strong... on both engines.... it is just a matter of getting it set up right....
Holley jets their carbs somewhat rich on the idle circuit.... I had to open up the idle air bleeds on all my holley carbs to lean them out at idle.... from the factory main jets, you should not have to go up or down more than a couple of numbers to get the jetting right....
the secret to setting a holley carb up right is ,,,, SET IT JUST LIKE THE FACTORY SAYS TO..... FLASH,,,,holley wants it to run really good , just like you do.....
a 600 holley will run good on any size engine that you put it on,,, from 289 to 455.... it is one of the most versital carbs out there....
putting a bigger carb on makes a given engine get what it is going to get quicker.... and moves the power up the rpm scale.... a small carb comes on strong on the lower end, [which is where we drive most of the time] and a bigger carb comes on strong further up , toward the high end.....
But dollar for dollar a holley carb will hold its own with any carb out there.....p

 

Do what they say here for adjusting the idle mixture screws to get highest vacuum at idle:

http://www.holley.com/TechService/FAQ.asp?category=Carburetor

Scroll down to post number 5 where Nick talks about the jetting on his Holley 750:

http://www.v8buick.com/showthread.php?224070-Stock-Buick-350-Skylark-runs-12s-in-the-quarter

Here is more jetting info:

http://www.v8buick.com/showthread.php?190920-Next-test-Holley-DP-vs-Vac-Secondary&highlight=