Holley 750 vacuum/can I remove this?

[patrickt]

Gary's absolutely right. With today's gasoline and, I'm guessing your carb might be tilted a bit as well, you can no longer rely on the fuel level at the bottom of the sight hole method for setting floats (which you could on a nice Galaxie with Sunoco 260 in the tank). What I do is set it to the bottom of the holes, run the car until it's hot, pull the air cleaner and watch the boosters drip. Light up a Lucky Strike while one of your kids/grandkids films you with his phone. Once the car cools down, drop the floats slightly and repeat. Keep doing that until you no longer have booster drip from shi**y gas percolation. That's the best way to set your floats. For the air bleeds, blast a good carb cleaner though all eight bleeds, then set your compressor down to about 40psi and blast some air down through them. Then repeat. Your carb is now 75% dialed in. Setting the idle mixture screws just right (mine are set at 1 and 3/20ths turns out from lightly seated) is your next step. Then set your primary throttle plate so there's just a little bit of the transfer slot below the plate (you do not need to pull the carb off to do this, you can see this by looking down the top of the carb). Then get your idle RPMs just right by adjusting the secondary. You're now better dialed in than 98% of the carbs out there.

EDIT -- Don't light up a smoke while you're checking out the gas percolation cloud.

[patrickt]

With a Holley 750 vac secondary, I can't emphasize enough how having the idle/transition circuits tuned just right can make a HUGE difference in your overall quality of life. Seriously, the idle/off-idle/transition circuit is really important when you're just driving around town, at low speed, and gently accelerating. It's the difference between the carb being "just ok" and it being great. And to get that circuit just right, easily, you replace the hidden screw on the underside of the carb, that controls the opening of the secondaries, with a 25 cent mod like I have right here. You then adjust your idle RPMs with a little Allen wrench. That screw, btw, is 10-32.

[Gaz64]

Originally Posted by patrickt

Gary's absolutely right. With today's gasoline and, I'm guessing your carb might be tilted a bit as well, you can no longer rely on the fuel level at the bottom of the sight hole method for setting floats (which you could on a nice Galaxie with Sunoco 260 in the tank). What I do is set it to the bottom of the holes, run the car until it's hot, pull the air cleaner and watch the boosters drip. Light up a Lucky Strike while one of your kids/grandkids films you with his phone. Once the car cools down, drop the floats slightly and repeat. Keep doing that until you no longer have booster drip from shi**y gas percolation. That's the best way to set your floats. For the air bleeds, blast a good carb cleaner though all eight bleeds, then set your compressor down to about 40psi and blast some air down through them. Then repeat. Your carb is now 75% dialed in. Setting the idle mixture screws just right (mine are set at 1 and 3/20ths turns out from lightly seated) is your next step. Then set your primary throttle plate so there's just a little bit of the transfer slot below the plate (you do not need to pull the carb off to do this, you can see this by looking down the top of the carb). Then get your idle RPMs just right by adjusting the secondary. You're now better dialed in than 98% of the carbs out there.

EDIT -- Don't light up a smoke while you're checking out the gas percolation cloud.

1 and 3/20ths?

Gary

[patrickt]

Originally Posted by Gaz64

1 and 3/20ths?

Gary

Yes. I know it sounds a bit anal, but I have a clickable very small ratchet that has exactly 20 clicks for one complete revolution. I use that tool to adjust the idle mixture screws. The perfect amount for my calibration is 23 clicks out from lightly seated. Not 22, and not 24. There's actually a feelable difference from just one click, one way or the other.

[Gaz64]

Originally Posted by patrickt

Yes. I know it sounds a bit anal, but I have a clickable very small ratchet that has exactly 20 clicks for one complete revolution. I use that tool to adjust the idle mixture screws. The perfect amount for my calibration is 23 clicks out from lightly seated. Not 22, and not 24. There's actually a feelable difference from just one click, one way or the other.

Ah yes, makes sense, and now for others following as well.

Gary