By the way, just pulled a 445 out of my 71 4x4 F100 for a suspected bad piston. Slapped a little bench build 390 in it. Clean little motor, but should be a HECK of a drop in power
Before: 10:1 445, zero deck, ported iron heads 2.09/1.67 undercut stem, good valve job, ported RPM, 1000 HP Holley, SFT Bullet cam, close to Comp 282S but little more lift and 112 LSA on 106
Now: 9.3:1 390, .004 below, stock replacement 2.02/1.57, not ported, decent valve job, stock Streetmaster, 750 Holley, Crane 272 (Very close to a 268H intake lobe) 112 LSA on 109
Thinking 175-200 hp less? LOL I'd say that would be a driving difference, but a quiet engine will allow me time to get the Zyglo out and figure out if I have a cracked Probe piston...
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