Most racers now days want to run open bottom plug tubes with this little dog bone plug tube retainer you can do so with confidence that plug tubes are locked down in the valve cover and there will be no leaks.
Plug tube retainers are .090" thick alum. with a 1.775" center to center bolt spread. Holes are set up for 8/32" fasteners.
Racer must have the ability to drill and tap sixteen holes to install these on their valve covers.
Dual plug tube retainers are sold in sets of eight.