Looks like the original factory intake on the 413 pictured above. Same one that was on my 413 industrial/motorhome engine. Raised carb pad and 4 hole plenum.

I've never built one, only examined the one I have in the pic below.

413 stand.jpeg
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