Offset pins are a wonderous thing. If you draw it out it's easier to see. When the piston is at TDC, the crank will not be at TDC. Depending on which side they offset the pin to and how they get installed. When the crank and rod at in line with each other, the pin is the farthest it can be from the center of the crank. When you offset the pin, this means you'll have a slight angle between the rod and the cylinder when the piston is at TDC. This reduces piston rock and also decreases the max acceleration at TDC giving less load on the rod and also helps the piston transition from one side of the cylinder to the other without slapping it real hard. The other result is less side loading for the same rod ratio as a center set pin. When you draw out the kinematic diagram, you end up with an offset slider and crank.
IMO for the 347 combination...if you go with the right company oil burning is not going to be a problem.... for the pistons it is all in the skirt design. Many companies such as Probe, DSS and others had problems with oil control due to the skirt design. got a 347... though i didn't build it.... no problems yet.. [looks for wood to knock on] but I am building another motor though, it will be a blown 331... gonna make it simple with a 5.400 rod.
