[Amc-list] piston pin offset

[Doug Dornbos <dornbos@xxxxxxxxxxx>]

Hi all

the Jeep Engines Book says on p. 140 (pertaining to the 4.0):
"Factory pistons have the pin offset to reduce piston slap. By
reversing the offset (reversing the piston), you can reduce engine
friction."

and then on page 142 (pertaining to the 4.0):
"It's commonly known that you can turn pistons around. The piston,
when originally made, has an offset pin. This offset pin makes the
engine run quieter. By reversing the piston (the arrow on the top of
the piston now points to the rear of the engine instead of the front
('stock' installation position), you reverse the centerline placement
of the pin. This makes the engine noisier, but it will also produce a
little more torque."

and then on page 212 (pertaining to the 4.2):
"The piston pin boss is "offset" from the piston centerline to place it 
nearer the thrust side of the piston. To ensure correct installation of 
the piston in the bore, a notch is cast into the top perimeter of the 
piston head. The notch must face forward."

here are my questions (specifically in regards to my 4.2):
1. does it change the effective stroke and/or the effective
compression ratio to turn the piston around?
2. if I switch to Chevy pistons, will they have an offset pin? if not,
what are the implications of using a non-offset piston in this
application (258.)
3. can I just simply take the pistons & rods out of the hole, turn
them around backwards and put them back in? or is there more to it
than that?
4. does anyone have experience with this?

thanks in advance.
Doug Dornbos
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