My GTbird build
Reply #23 –
Actually instead of me sounding like a ass I will give my explanation.
The HV pump will only provide the extra volume if the engine needs it. Its all dependent on bearing clearances. As bearings wear and clearances open up that's when a HV pump earns it keep. I didn't turn my crank on this rebuild as all bottom end clearances checked out ok but at the high end of good. Obviously these clearances aint getting any tighter after I put about 600 miles a week on this motor so this is my insurance I will get a long life span on this rebuild. As clearances open up I will still have the volume there for good pressure even with thin oils on a hot motor sitting at idle {think lots of Detroit expressway driving}.
The gear failure everybody talks about was a much bigger problem back when 99.9% of Ford cams were cast iron with cast iron distributor gears. Yes they would fail with HV and HP pumps. After Ford switched to steel roller cams and steel gears it is much less of a problem now as these parts are much stronger. In fact I have only seen distributor roll pin failures and twisted shafts myself on 5.0 motors with roller cams. I have yet to see a gear failure.
That said... I did buy a good ARP driveshaft and I will be running a Comp Cams Poly distributor gear which are indestructible.