Re: Henry's 55 Constellation

Posted by 55PackardGuy On 2011/1/6 22:40:51

Overboring for cylinder wear isn't really a modification, it's just maintenance.

Here's a little formula from Steve (58L8134) over on the Modifications board for figuring cid based on bore and stroke.

Cubic Inch Displacement= Bore (squared) X Stroke X 0.7854 X Number of Cylinders.

The Packard 352 has a 4" bore and 3.5" stroke, so .030 over would yield about 357 ci. Pretty cool number.
.020 gives you a 355.

As far as keeping it "stock," your current .012" of wear doesn't work out to a perfect 352 any more either. But by any other displacement, it's still a "352" Packard engine, because that's how it started life.

Now a radical overbore or stroking the crank, then you're really talking a "modified" non-stock engine.