Motorcraft & Holley 2 Stage Power Valve 70-1000

1. What is the 70-1000 power valve compatible with?
The 70-1000 fits Holley 4-barrel and Motorcraft 2-barrel carburetors that use 2-stage power enrichment systems. It’s made to OE specs for vehicles designed with a 2-stage valve.

2. How does a 2-stage power valve work?
It opens in two steps:

• First stage opens at moderate vacuum drop (e.g., ~7?"Hg)

• Second stage opens near wide-open throttle (e.g., ~0.5?"Hg)
  Each stage adds extra fuel as load increases.

3. What engine conditions is this for?
When cruising, your engine vacuum is high, and the valve stays closed. During acceleration or load, vacuum drops—triggering the first and then second stage—providing power enrichment.

4. Can I swap a 1-stage valve with this two-stage valve?
No. Using a 2-stage valve requires a larger power valve cover. Simply dropping it in place of a 1-stage will cause excessive fuel and flooding.

5. How do I know which valve rating I need?
Check your engine’s manifold vacuum under load and at wide-open throttle. Choose stage ratings that match those vacuum levels. For example, a 7?"Hg lower stage and 0.5?"Hg second stage are common.

6. Does a gasket come with the valve?
Yes—a gasket is included. Make sure it’s centered correctly, and if your valve body has a recessed area, set the gasket into it.

7. How do I install a power valve correctly?
Seat the valve in an inverted metering block to keep the gasket in place, then torque it down. Use silicone spray and a thin bead of gasket maker around—but not on—the gasket edge for a better seal.

8. Can I adjust this valve once installed?
No. These valves are preset and not adjustable. Tampering may cause incorrect fuel delivery and engine performance issues.

9. What if I don’t use a two-stage valve?
Using the matched two-stage valve where needed ensures better drivability and fuel efficiency, especially during load and cruise conditions commonly seen in heavier vehicles.

10. Is this part in stock and ready to ship?
Yes—the product page reflects in-stock availability, and orders placed before 12?PM PST (Mon–Fri) normally ship the same day.

11. Can this cause flooding?
If installed inappropriately—such as in carburetors designed only for 1-stage valves—excessive fuel delivery due to the unmatched valve is possible and not recommended.