A question on holley carbs

[S-Car-Go]

My uncle gave me a used holley 670 SA because my current carb is a little small for the application. I was checking it out before I installed it and noticed the transfer slots are different lengths, both primary and secondary sides. With the carb upside down if you set the butterflys so the t/s on one side is square (just showing), then the other side is either completely covered or has twice as much showing. Is this common and will it give me problems? Is it better to have too much showing or not enough? This on both front and rear sets of barrels.

 

[woodsnake]

I'm sure it is an engineered feature, not a flaw.

What is the rest of your combo?

 

[D.Hearne]

I'd just set it and see if it runs correctly. I never set it based on the slots. Screw the mixture screws in all the way, then back each out 1-1/2 turns. The back out the idle speed screw all the way, then in just enough to where it moves the throttle blades off the closed position. Bolt it on, set the initial timing, then crank it and set the idle where you want it using the idle speed first, then the mixture screws. If it doesn't run that way, then you may be correct in your suspicion about a problem with the slots. I'd also remove the bowls before bolting it on to insure there's no trash in em. And if it's sat for any length of time more than a few weeks, you'd be doing good to replace the powervalve and the accellerator pump diaphram before using it.

 

[S-Car-Go]

Already replaced gaskets and PV. Thinking back on it, my uncle never cared for how his truck ran with this carb (72 cheby, 350). This may have been a contributing factor or just a bad tune.

I'll probably hang on to this carb for an emergency. I can't think it will run at its best like this. It may run, but not at the most efficient. This is my DD unless it's raining.

Rest of the motor is a very mild 331, Canfield 170, 9:5 to 1, Lunati 610001
(213/219*, .480/.500") flat tappet, Wieand Stealth with a 1" open spacer, FPA long-tubes. It's got a Holley 570 SA now from when it was a 289.

 

[D.Hearne]

The 570 is only going to limit the topend on your 331. My 331 is a bit wilder with Canfield heads too, (might be the same as yours, I don't recall the model numbers) more cam (Ford Z303 w/1.7 rockers) 1 point more compression. It does fine on just the center 250 cfm carb (3x2 setup) around town and on the highway.