I have a 72 duster with a recently rebuilt 225 with quite a bit of head work. I have a MP cam in it with .460" lift and 268 deg duration. When I installed the engine in and used the factory timing specs and it runs good and strong. Does anyone have any suggestions as to advancing or retarding the timing for a little bit better performance for this setup or or should I stick with the factory timing specs?

Ok, for a new engine I wouldn't advance the timing more than a couple deg. for the first while, then advance it up from there. Pretty much just use a timing light and advance it till it starts to ping when you accelerate with a load on then back it off a couple deg.

done

Justin

Yes, try advancing it some to see if it runs stronger.
Also check the total amount of mechanical advance, 32 to 34 degrees is about right.
DD