next step air fuel ratio meter or

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abodyhotrod

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i'm running a 750 dbl pumper on a 30 over stock build 360 with every bolt on.the only thing left to do is crank, rods, and pistons.
the car runs tits, but i get worried running it past 5 grand. it does have the stock 5/16 fuel line and to me seems to lean out up top (starts to miss sumtimes). a fuel pump and new lines are in the work.(any suggestions)
now an air fuel ratio meter sounds like my best bet or is it just a waste of alot of money. i do have an extra spot in my new dash for an extra meter and was torn between air fuel or trans temp.
this is a street strip car and for now a daily driver. the stroker kit in the next year, for now just getting ready.

727, cheeta valve body w/shift kit
3800-4200 converter w/ b&m trans cooler
4:11 moser 60
10.5 mickey street ets
comps slide a link traction bars
3 in. x pipes w/3 in. tti's
msd e-curve distributer w/coil only
mighty demon 750
m-1 intake
stock eddy heads w/ thin gasket and 1.5 rollers
480-480 lunati cam
4 core w/ electric fans
fuel cell and batt. in trunk

so before i go wrench her down the track i want to make sure she's tuned right. i really dont want to make 20 passes just to get it dialed in.

what would you do to this dart? 11 sec. here i come.

thanks abodyhotrod

IMG_2494.jpg
 
I ran a vary similar setup in mine last year with junk 5/16 line and a holley blue electric pump and a 150 shot of juice. I didn't notice any missing, but the pump was really noisy. I think it might have something to do with the small line size. Anyway I would go to at least 3/8 line front to back as well as tank pickup and a electric pump. Good luck, she should rock and roll.
 
Somebody correct me if I am wrong but isn't that a whole lot of carb for a "stock" build 360. By the way the ride looks hot!

X
 
Over carbing is a myth, if you tune a carb to perfection, then it will work. A 750 is not too big for a 360, in fact, I know of people who run 850 carbs on built 360's. Actually a 650 might be too small for a 360.

As for the fuel line, I agree, stock is too small, buy the Summit fuel line kit #6, it has what you need for about $80. Also, I have an A/F meter that I ran on my old Dakota, I am selling it, but I have a buyer that is supposed to pay me today for it, I will let you know if he does not come through.
 
done deal parts were ordered earlier, new carter fuel pump, 6an steel braid fuel line, and a dyno type air fuel ratio meter so i can use on all my cars.
soon i should be ready for the track.
 
Before you start, I'd reconsider the -6 line. If you're putting it in, I'd go with AT LEAST -8 if not -10. Both will take of future needs. -6 might not. I put 3/8 aluminum line in mine and wish I'd run 1/2" for later.
 
The carb running lean at a higher RPM can be the carbs fault or actually, not tuned just right to the upper RPM's it's in.

A 750 isn't to large for a stock rebuild, but I would myself gone smaller. A 650.

The myth of to large a carb is true to a point. If you tune it well, it'll work fine. I myself have done a 850 on a otherwise stock 318 equiped with a 360 iron intake. I wasn't to fond of the low RPM (Off idle) feel of it. But it worked until I replaced with a different unit more suited for what it was doing.

The thing with carbs is the primary bore size can be a bit large for the amount of velocity the venturi is seeing. Fuel metering can be hard to get dialed in just so.

The mix of a large carb, like an 850 and Hwy. gears like 2.76's can be very difficult to get adjusted nicely. This is where a smaller 650 comes in feeling and probably performing better because of the smaller venturis and high velocity the carb see's. The fuel is easier to meter and atomizes better.

Again, any carb can be made to work, how well is another story. Your abiltys will play a big roll. It is easier to go smaller.
 
rumblefish360 said:
The carb running lean at a higher RPM can be the carbs fault or actually, not tuned just right to the upper RPM's it's in.

A 750 isn't to large for a stock rebuild, but I would myself gone smaller. A 650.

The myth of to large a carb is true to a point. If you tune it well, it'll work fine. I myself have done a 850 on a otherwise stock 318 equiped with a 360 iron intake. I wasn't to fond of the low RPM (Off idle) feel of it. But it worked until I replaced with a different unit more suited for whatit was doing.

The thing with carbs is the primary bore size can be a bit large for the amount of velocity the venturi is seeing. Fuel metering can be hard to get dialed in just so.

The mix of a large carb, like an 850 and Hwy. gears like 2.76's can be very difficult to get adjusted nicely. This is where a smaller 650 comes in feeling and probably performing better because of the smaller venturis and high velocity the carb see's. The fuel is easier to meter and atomizes better.

Again, any carb can be made to work, how well is another story. Your abiltys will play a big roll. It is easier to go smaller.
Click to expand...

i gotta agree with rob here. i run a 750 vs holley with a proform main body and rear metering block, 72/80 jets on a 360, eddy heads, 10.75:1 compression. i can pull this to 6 grand no problem, she does not miss. i would check (just for peace of mind) that #5 and 7 plug wires are not torn, to close for a good amount of length.
 
I didn't think about the 5 & 7 plug wires being crossed. I just remembered the carbs air bleeds. I'm not up on air bleeds. I understand what I read and talk about with others, just haven't been there myself.

I don't know if the air bleeds apply to your carb, as in adjustable/swapable etc.....
 
as for the miss it was my coil wire not snapped in.(stupid me that was my anti theft device for when i parked outside on the street).ran like that for a good week.

now with the air fuel meter i can tell that fuel is not a problem. the first reading i got was 12.5 at idle. when i put her to 5000 rpms under load she'd spike 9 and hold 10 11, to rich. jets were 76 and 83 since changed to 74 81.

still in tuning but car is driving better than ever already and must say the air fuel meter was not a bad idea.
 
That FAST unit is a bit pricey, but, it's my next toy. I see a bit of value with that. Even more so in a running car going down the road or track.
 
I have a wideband sensor in my 340 duster. On the street the a/f ratio is in the 12s. This is quite rich, but is it unusual?I know on the modern cars are around 14.7.

Ive got a mildly built 340, mopar purple cam(.484 left) headers, 650 holley.
 
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