Need advice , 75 360

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dodgegtdart68

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Ok so I have a 68 Dart GT. The original 318 bit the dust n someone put in a 1975 360. I had it rebuilt. Not sure about all the peticulars I lost the paperwork in this 15yr ( thru a divorce ) restoration. The motor has 322HP with 3" dual exhaust. Thrush mufflers. Here's the carb I have, been told by someone knowledgeable I should have a 650 vaccumn 2ndary. What I have is a 750 double . Here's the numbers n a pic. 1 what jets do u all recommend and any other info ??

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What I see is a 750 vacuum secondary. I would start with factory jets that the carb came with and let the car decide what it wants
 
It really depends on the rest of the build- heads/port work, cam, gearing, etc. Every build is different.
That said, there's no reason your 750 can't work just fine.
 
That 750 VS is a great carb for your street ride. Google the list number to make sure it has proper jetting & power valve. "And then drive it like you stole it".
 
I’ve found there pretty good OOTB and needing inky minor tweaks. Particularly the secondary side with the opening rate and when.
 
I agree totally with other posts, that carburetor should do a very good job. Might be a little more than you need and it will be hungry but if it's working right performance should be great
 
carburetion and rear gear ratio are very close related in the way that the motor will wind quicker the gear ratio is high and that accommodates a larger carburetor when the gear ratio is lower or taller it takes longer for the engine RPMs to rise and accommodate the larger carburetor for that reason a smaller carb may work better for your setup but vacuum secondary carburetors will compensate somewhat for those conditions allowing you to run a bigger carburetor on a given combination
 
I'll just throw out there that I ran a 750 double pumper on my basically stock 360 with stock converter and 2.45 gears and it worked flawlessly. It outperformed a 600 eddy and 770 VS at the drag strip, at every point including 60 ft time. No way, no how is that 3310 even remotely close to being too big for your 360.
 
318willrun said:
I'll just throw out there that I ran a 750 double pumper on my basically stock 360 with stock converter and 2.45 gears and it worked flawlessly. It outperformed a 600 eddy and 770 VS at the drag strip, at every point including 60 ft time. No way, no how is that 3310 even remotely close to being too big for your 360.
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that sure wouldn't be the setup I'd go with but hey if that's optimum to you
 
K.O. SWINGER said:
that sure wouldn't be the setup I'd go with but hey if that's optimum to you
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Asking, not arguing. Would you have went with one of the slower carbs? I have 1200 CFM's right now on a basically stock 318 with home ported heads, summit cam. stock converter and 2.76 gears. Performs excellent! And yes, I know it isn't using all 1200 cfm's... LOL. Truth is, No carb flows any more than what the engine will take. So, if his 340 will only flow 595 cfm's, guess what, that 3310 is now a 595 cfm carb. :)
 
318willrun said:
I'll just throw out there that I ran a 750 double pumper on my basically stock 360 with stock converter and 2.45 gears and it worked flawlessly. It outperformed a 600 eddy and 770 VS at the drag strip, at every point including 60 ft time. No way, no how is that 3310 even remotely close to being too big for your 360.
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Sweet thank you , what jets are u running in it ???
 
318willrun said:
Asking, not arguing. Would you have went with one of the slower carbs? I have 1200 CFM's right now on a basically stock 318 with home ported heads, summit cam. stock converter and 2.76 gears. Performs excellent! And yes, I know it isn't using all 1200 cfm's... LOL. Truth is, No carb flows any more than what the engine will take. So, if his 340 will only flow 595 cfm's, guess what, that 3310 is now a 595 cfm carb. :)
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I'm going with this carb because it was convenient.nthe guy that had it used it on a basically stock 68 440 , he ran 72 jets and recommended 67 for mine.
 
dodgegtdart68 said:
Sweet thank you , what jets are u running in it ???
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Honestly, too many carbs and I don't remember LOL. Seems like 72/80, but I could be wrong. It will have to be "your car specific" anyways.
 
I'd start with 67 or 68 jets & check the power valve, it should be a 6.5 from the factory. From there, drive it & then read your plugs to see where you stand (rich or lean). Just make sure it isn't blown out, all it takes is one backfire & the car will run so rich you can't stand it.
 
Remember, if the carb is a touch big the motor will run lean. The engine doesn’t produce enough air flow, so the signal is weaker. I’m a big advocate of AFR gauges so here is my pitch. Its pump gas so the O2 gauge will live for more miles than you will ever drive in it. It gives you realtime info and say you are driving along and the car acts up. They all do sooner or later, you look at the gauge. For the vast majority of the time if it suddenly goes lean, its fuel delivery. Suddenly goes rich it is ignition. You have just cut out half of the probable causes. A bit over $200 so not cheap, but for me it is third in line. Oil pressure, water temp, AFR. Distant fourth is alt gauge. Not charging for me usually means the belt is gone. Catch it quicker than seeing it start to get warm.
 
That's one of the best old school carburetors money can buy. You gotta goodun.
 
furrystump said:
Remember, if the carb is a touch big the motor will run lean. The engine doesn’t produce enough air flow, so the signal is weaker. I’m a big advocate of AFR gauges so here is my pitch. Its pump gas so the O2 gauge will live for more miles than you will ever drive in it. It gives you realtime info and say you are driving along and the car acts up. They all do sooner or later, you look at the gauge. For the vast majority of the time if it suddenly goes lean, its fuel delivery. Suddenly goes rich it is ignition. You have just cut out half of the probable causes. A bit over $200 so not cheap, but for me it is third in line. Oil pressure, water temp, AFR. Distant fourth is alt gauge. Not charging for me usually means the belt is gone. Catch it quicker than seeing it start to get warm.
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Fill me in on AFR gauges , such as what are they ???
 
don't care for Holley carbs myself. Any Holley carbs. Never did.
 
Yep, you weld in an o2 bung on the head pipe. It shows realtime whether the car is running rich or lean. The same sensor is used for fuel injection cars to tell it how much fuel to inject.
 
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