quick fuel 750s

[cjshaker]

A friend of mine that used to run Super Stock in a Hemi, often talked about the thousands of dollars that guys would spend having their carbs 'worked' by some pretty smart fellows, just to gain that last .001 in ET. I know carb work can get pretty involved when you get down to the nitty gritty, but us mortals mostly stick to basics. That's why I asked questions, just to gain a little knowledge, because those guys are pretty protective about what they know.

[cattleFEeder]

Stangman these guys have some, if there listed there are in stock. Just depends on your checkbooks pain level. Good luck Dan
http://www.cobranda.com/39duqumeriin.html

[Falcon67]

Depending on the engine configuration, it may make some difference - or not.  I have run a 650DP against a tuned 750 VS that flowed more like 840 - no difference in MPH or ET.  YMMV as they say.  Generally with a VS you are running on half the carb until you get enough air flow to make it do other things, so they have a wider range of operation than you'd expect from a similar double pumper.

[Stangman]

Thanks cattlefeeder they sold there last one last week I missed it by 5 days. The story of my life
always alittle late.

[Stangman]

Well hopefully i will get them before june 23rd, going to 1/8 mile track that weekend.
will let you guys know. Thanks for the inputs.

[Tobbemek]

If you want 2 600 1850is, .excellent performing and top tuned and to a super price, get Drew to build you a set. Heck he even tune them on his own Galaxie before he ship them out, what could possible bee better???

[Drew Pojedinec]

what could possible be better???

Doing it for free?  Tuning them at the track?  giving me a month to tinker with them instead of 2 days?   Lotsa things really could be better.....   

I'd actually be interested in Stangman sending me his old 1850's, I'll recalibrate them and send them back and he can do back to back tests with his new 750's.

[Stangman]

Drew they are those aluminum ones that you cant adjust the floats from the outside, you need to take bowl off.
Also no sights on bowls, except one that I put a regular 600 bowl on. That is one of the reasons why I wanted to
go this way. I was having a problem and I adjusted the floats alittle higher, and because I was going to the track I bumped the jets up alittle I f I remember correctly they were 64 stock and I went to 68, or they were 66 and they are at 70. I dont know how much can be done with these. 

[Drew Pojedinec]

Sounds like the 80457's, those are set really weird and often dangerously lean.  You'll certainly like the new 750's you have....

[Stangman]

there 1850s whatever that means if you look in jegs the 80457s looks like it has float adjusters, its the one with the gold in it.

[Stangman]

Went up this weekend to PA and got rained out. The carbs are on and they started right up set regulator to 6 psi and the floats were at the very top of the sight glasses so I lowered them to
The middle of glass. Seemed rich so I took out the 72 jets and put in 68s. Adjusted the idle mixtures and it idle well about 9-950 at idle and 800 in gear and smooth.When I give it gas it gets up without a bog but then at low cruise say 1500-2500 it’s not right. If I get past that it runs better and clears up.
It’s almost like at cruise you can hear in the exhaust like a thousand little misfires, almost like maybe a lean miss. At the track being I know the owner when I got there the day before on Saturday I took my nephew down the unprepped track and obviously even after a burnout had no traction but it got up and went with no hesitation, but without traction the car didn’t have a load on it so I don’t know if that is a good test. Any ideas what I should be looking for. I didn’t have this with the 600s. They have the same 6.5 power valves as each other, although the Quick fuels have adjustable everything. I’m not bad with carbs as far as floats, jetting, mixtures but all these adjustable bleeds and stuff are above my pay grade

[Falcon67]

Light throttle cruise misfire - lean primary.  Put the 72s back in, or at least go up two steps to 70s.  If it seems "fat" at idle - two things:  1) it's lean, not fat (the smell is unburned fuel) and 2) jets don't do anything for idle.  Each jet change is more or less 3% fuel, so you took 3x4=maybe as much as 12% of primary fuel out of it.  That is a LOT.

[Stangman]

I am off for a week starting on Monday so I can do a lot to the carbs. Ya know it’s my fault
I shouldn’t have changed jets before driving it. The car was in the trailer. Another thing that is bothering me about the carbs is one of them had an imperfection on the part that the gaskets seals around the fuel inlet, I used some 1500 sandpaper to get it out but before I saw it I kept snugging up the banjo bolt it was bothering me that I had to make it that tight now I’m leary about taking it off and on. But I will start from scratch. Thanks Falcon 67

[Tobbemek]

First MJ is more depending of venturi size than engine, look up what a Holley 4779 list nr: is in jetting ore QF listing inkl, PWR. and start from there. IFR is a more depending on intake vacuum and throttle bore size and if you have tho carbs you have to get them smaller ( intake vacuum sucking from twice as much fuel jettings on idle and part throttle ).
The right presidier is to go stupid lean on every circuit and bring it back up in jetting running good, except WOT that always should bee in 12.5 to 13 AF/R ratio.  One can never hurt a engine on light load looking fore the right tuning remember that, you will only hurt it on WOT if it is wrong jetted in the MJ curcuit. Lean part throttle function requires allot of advance timing to function properly, that's were most BILLET distributors with out vacuum can gets lost.

[Tony Fritz]

Stangman. here's my two cents worth.....I have 5 sets of carbs that I have played with over the last couple years. 1850's, modified 1850"s, Re-issued BJ-BK's, 660's and a set of Barrys QF 750's. Barrys QF 750's are more responsive and crisper. I've had them on 464's, 482's MR & HR etc....built similar to your motor. Bottom Line...IMHO you are going to like the QF 750's !!!