Our billet girdle is made from 7000 series aluminum to add significant rigidity to the VR38 motor. 7000 series aluminum is strong, with a strength comparable to many steels, and has good fatigue strength and average machinability. It has lower resistance to corrosion than many other Al alloys, but has significantly better corrosion resistance than the 2000 alloys.
We have seen uneven bearing wear due to the block flexing with the stock girdle and this problem is resolved with our billet girdle and upgraded ARP Oversized Main Bolts. Reducing the amount of flex in the block prevents premature bearing wear and improves the longevitivty of the bottom end as a whole.
Our billet girdle is designed to only require a line hone, rather than a full line bore like our competitors billet girdles.