Chainsaw Repair

Picked up a CS56 (Efco956 or 156 must be a 956) crankcase, crank, P&C, carb, flywheel, coil, air intake system basically the motor minus the rear handle, bad crank bearing.  Wanted to use P&C for a 158.  Cylinder is single tranfer like a 272 Husky.  Robbed a piston out of a new 156 Efco for a customers saw.  Got out the 156 cyl. to compare to CS56 to decide which one to use.  The 156 cyl is dual transfer like a 372 Husky with a bridge in the top of the intake port.  I was suprised to see the difference.  After seeing the 156 cylinder I know why they are so strong for 46mm.  OILogging what did the cyl. look like on the 158 you built?
Shep

I was comparing my 156/956 46mm piston to 162/962 48mm.  The newer 156 and 962 have a bridge in the middle of the intake port.  The 156 46mm has ring locating pins on the left and right on intake side (limits widening the intake).  The 962 has the top ring pin centered in the  intake.  Lower ring is on ex side well out of the way for widening ex.  Since both have the bridge can I move the ring pins on the 156 piston to the same location as the 162?  Looking @ them I don't see why not.
Just bought a KIC brand (seller said they were Tiawan) 156 46mm piston.  Am very very impressed with the quality of this piston. Very minimal flash in the windows interior casting excellent, etc.  He has 1 more I may buy it just to have in stock.  I'm liking this saw so much I'm getting rid of my 55 Huskys.  That's hard for a Husky man to do but this saw is way beyond a 55.
OIL what porting did you do on the 158?  The upper transfers don't look like there is much you can do to them except raise them?  Also, what timing numbers did you use on the 158?
Shep