Those short 4500-4150 adapters look like they'd be so restrictive that you wouldn't see any performance increase from the bigger 4500 carburetor. Looks to me that if you can't use the taller adapter with a smoother transition, then you'd be better off staying with a 4150 carb or getting the a 4500 flange manifold.  CHIP
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
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