Do you have new OEM hinges? They have directions on how to install.
I have to tell you, if these hinges are anything like the full size weld on, DON'T DO IT!
I am not kidding you, they are a total PITA, one of the worse designs I have ever seen. Those hinges are plug welded from the back with a HUGE 1/2" or so diameter welds. After grinding the weld off the front and removing the hinge you have to drill the four holes and then insert a stud that is on a "fishing line" spring like device thru a hole in the cowl up thru the bolt hole from the inside of the cowl side. Then, this stud is "supposed to" be pulled into the hole by the nut and sort of swedge into the hole. BS, the friggin giant weld on the inside prevents the stud from setting flat as it doesn't stay.
The book gave some ridiculas amount of time like four or five hours a hinge to install. I said YAHOO, I'm in the money, I will kick *** on this job. Yeah, RIGHT, it took me all day to do that friggin thing.
LEAVE THE ORIGINAL HINGE AND REPAIR IT. That's my advice.