If the monte carlo bar fits between the shock towers then it is drilled wrong. If it doesn't fit between the shock towers then the shock towers have started to collapse. Someone else on the forum had this problem with a monte carlo bar where the holes did not line up but I forget where they bought theirs from.
I got mine from Texas Mustang and the holes aligned perfectly. I had to jack the car from the crossmember to get it to drop in but the inside holes worked. I've heard of people having theirs 1/2 hole off or more.
Most of Monte Carlo Bars out there NEVER are bolt in deals. If you want to see IMHO the best one out there and serviceable check out Street and Tracks quick removeable verison, very good quailty will it fit better, not really sure but dam site better than what you will find at most vendors.