off topic datsun question

[Waylon Harthun <jackfrost@uswest.net>]

I am running an L20b motor in one of my cars. I recently replaced timing 
chain and gears in the motor but I seem to be having trouble with run on 
after I turn the key off, sometimes followed by a backfire. can someone 
tell me what a good running setting for the timing should be. also could it 
be a problem with the carburetor?  Any help would be grateful.
                                                Waylon Harthun
                                                65 1500