The idle speed is a little high with the new Holey. I cannot seem to lower it using the screw on the bracket either. And if I mess with the two screws on the side (in the metering block), then my car tends to stall. I have also been told that jet size has nothing to do with the idle, but when I switched from #72 to #68, the idle (and everything else) started behaving a lot better.

Do I need to look at different power valves or metering blocks? I am assuming that the metering blocks are all the same, I just need a smaller power valve...

This is a 750vac.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

 

The screws on the side of the metering block are idle air mixture screws. Turn them in all the way the back them out 1 1/2 turns to start. Turn them both in 1/4 turn each until you get the highest vacuum reading.

Power valves have nothing to do with the idle. The power valve will probably have a 65 stamped on in. That means at 6.5 inches of vacuum and less, the power valve will open. With a typical idle of 17 inches, the power valve won't open at idle.

Check for a vacuum leak. I usually forget to put the power steering booster line back onto the back of the carb when I do a jet change. As soon as I start the engine it goes to a high idle and I know exactly what I forgot to do.

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Stephen's racing page

87 IROC-Z Pro ET Bracket Race Car
383 stroker (carbed) with double hump cast iron heads and pump gas
454 Big Block buildup now in progress for the 2001 racing season

Best results before the 383 blew up
Best ET on a time slip: 11.857 altitude corrected to 11.163
Best MPH on a time slip: 117.87 altitude corrected to 126.10
Altitude corrected rear wheel HP based on power to weight ratio: 476.5
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley