K-Member
, a grider should work. 
Well if you just bought them they should not have to be notched if they are an older set you may need too. Best way it just of fit them up there install two bolts mark it and remove them grind and reinstall. Every one's car is going to be just a little bit different and why you are there you ought to think about installing the Poly motor mounts it is alot easier with out the headers there just a thought it helps with the Y pipe banging issues that some people have and it sure won't hurt anything. Another optioon is to grind the K-member in a 5-6" section on each, but you would be guessing how much you need to take off and from where ETC... I used a BMR K-member so I never had any issues with mine sorry good luck.
