I'm pretty sure the wrist pin is pressed in on the 3400 like many US made saws of the era. Make sure the LRB wrist pin fits properly or reuse your old one to avoid having the wrist pin move once you put it back together. I know the wrist pins they supply for McCulloch saws are way too loose and will literally fall out. More than a few saws have been wrecked by mobile wrist pins.
The 3400's are notoriously low for compression, even with a new piston and rings so don't expect it to make 150 PSI when you're done.
Mark
The 3400's are notoriously low for compression, even with a new piston and rings so don't expect it to make 150 PSI when you're done.
Mark