With the stars in place, the collectors can be finish-welded onto the ends of the tubes. We added 21⁄2-inch branches that’ll feed into the muffled system when we run on the street. Three-bolt collector flanges (PN SUM15300, $7.69 each, 3 inches; PN SUM15212, $6.39 each, 21⁄2 inches) receive collector caps and under-car head pipes, respectively. Note that the branch on the right has not been welded yet. Back in the ’60s, we’d have applied high-temperature header paint to prevent rust. Today, we’ll send ’em off to one of the big commercial coating houses for application of a ceramic thermal barrier, inside and out.