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Ron Miller · 03-14-2009, 11:45 AM

As Blueoval Ralph suggested, I would open up the idle air bleeds .003 to .006 before I drilled the Primary throttle blades. I would rather mix the added air in the idle channel sooner than in the added holes in the throttle blades. Getting the idle mixture correct, you might see a increase in vacuum. Also use a good vacuum gage to adjust all your idle mixture screws. Adjust in park and check in gear. Adjust screws in or out to achieve the highest manifold vacuum. When idle is adjusted correctly their will be a increase in manifold vacuum. You will have to change the power valve. To choose the correct power valve, put into gear, foot break the engine to launch r.p.m. and look at vacuum gage. Example,,,,, if the vacuum reading is 9 to 8", choose a power valve 1.5 under that reading.

Ron

03-14-2009, 11:45 AM	#6
Ron Miller Member Join Date: Mar 2002 Location: Brownstown, Mi 48134 Posts: 196 Likes: 35 Liked 13 Times in 7 Posts	Re: Holley 750 dp setup As Blueoval Ralph suggested, I would open up the idle air bleeds .003 to .006 before I drilled the Primary throttle blades. I would rather mix the added air in the idle channel sooner than in the added holes in the throttle blades. Getting the idle mixture correct, you might see a increase in vacuum. Also use a good vacuum gage to adjust all your idle mixture screws. Adjust in park and check in gear. Adjust screws in or out to achieve the highest manifold vacuum. When idle is adjusted correctly their will be a increase in manifold vacuum. You will have to change the power valve. To choose the correct power valve, put into gear, foot break the engine to launch r.p.m. and look at vacuum gage. Example,,,,, if the vacuum reading is 9 to 8", choose a power valve 1.5 under that reading. Ron