The MP aluminum housing looks just like a stock one.
I'm running the 440 Source housing with a Flowcooler pump Right...and you were asking what to upgrade it with b/c of the small passage concerns with the 440 source housing. So I said the MP housing works great, doesn't have small passages, and looks stock.
CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 4 speed, Dana 60
'71 Demon 340, no drivetrain, on blocks behind the barn
'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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