Hello Doug:
I just discovered this bulletin board today
April 17, 2001.
I see your inquiry is from middle of last year.
You have a McCulloch 1000 which is a Partner P100. Partner started building these in 1978 and built the ones for McCulloch around 1980.
The parts will interchange. Partner built the engine as used in the P100 in the K1200 Cut-Off saw until 1999 or so. No parts problem for awhile. The displacement is 100cc. You can quite safely install a shorter bar, they were built down to 16"
Mike
[This message has been edited by Mike Acres (edited 18 April 2001).]