Problems with going into 2nd gear

Last night I decided I'd see what my cobra had. So I went all the way through first and then went to shift to second and all it did was grind and wouldn't go in. It does that every time I try to go into second while giving the car all it's got. But just daily driving it's no problem at all to get into second. I don't know if this car has an aftermarket clutch or anything about it's drivetrain history other than it looks stock under the hood. The clutch cable is factory. Thank you very much..