Proflow Freeze Welch Plug Kit, Suit GM LS Series Engines, Holden Commodores, Includes Billet Barbell & Block Hardware, Kit - PFEWP-3818026Part Number: PFEWP 3818026 Proflow's LS series welsh plug kit is a necessity when rebuilding your ls series engine. The kit includes all brass welsh plugs required, including a new barbell which is now made from 6061 aluminium. The new billet barbell replaces the factory plastic barbell which can become brittle and fatigue over time.