Rocker shaft hold downs

Recently bought the Hughes holdowns for a 340 & they are quite nice. Not sure what machining would be needed, mine worked great with the supplied spacers. It was also very easy to set up using feeler gauges to set the side-to-side clearances & get them properly centered visually. To stock stamped ones are much more tedious to set up as you typically have to file the ends of the stampings to get them just right. The only (minor) problem I had with the Hughes setup was the length of the studs, most were a bit too long on the portion that threaded into the heads & required shaving. No big deal but could be big trouble if you didn't notice & just torqued to spec.