gxnos - 347 pistons often do have the wrist pin intersecting the oil ring, but almost any modern piston designed for a 347 has a relocated wrist pin, or some form of oil support rail in the oil ring to correct this problem. It is an old problem which is mostly just a rumor today. 347 strokers say 10 or 15 years ago(or something like that) were based off a ground down 351C crank and utilized standard or overbored pistons which had the oiling issues you hear about now. Probe and SRP both make pistons which are used in the most common 347 kits which do not have any oiling issues.
As far as stress on the cylinder walls, a 347 does have a higher rod ratio which CAN lead to this. However, as long as your motor is assembled correctly and professionally, you will use a torque plate to simulate this stress while the block is overbored. Also, a 347 will often make power at lower RPMs than a 331, which helps to further reduce stress. I'm not saying this is always the case. Every motor is different.
"Block clearancing" can be done with a dremel tool or other grinder in probably an hour or so. I think my machine shop threw that work in for free when they assembled the rest of my 347 stroker. It is simply notching the skirts of the cylinder, and sometimes has to be done with a 331 as well. This is also often dependent on whether you use I-beam or H-beam connecting rods.
Please don't take this as a "347's are way super better than 331's!" post because that's not what I am implying. I just want people to realize that both motors will make great power as long as they are WELL BUILT. There are so many rumors about 347's that it's hard for anyone to find out the truth. The most important factor in building any stroker motor is to have it done professionally to tight tolerances.
