3.1L Interference engine or not

I Have a 91' 3.1L that the timing chain broke on. I have replaced the timing set. When trying to start the car it pops then starts but I have to hold the gas down about halfway, and it runs very rough. Mitchell repair says that you can set the timing with either the #1 or #4 cylinder, I used #4 and had the crank at the 12 o'clock and cam at 6 o'clock positions.

Is there piston to valve issues when the timing chain breaks, or am I missing something?

Thanks,

jnk111

I can take the bad news if this is an interferance motor :).

thanks,
Joe