Almost looks like someone made a "lid" for the original lid? Like they made a top plate for a 2x4 setup and grafted it onto the original Weiand lid. Then blended and smoothed the welds? Hard to see in that blurry pic, but just a possibility.

CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax