It really depends on where the speed was made. Sure you can do it if going down a slope and there are lots of them on the motorway, particularly between Islamabad and the salt range.
I once touched 135 on my ex-mehran on CNG. Didn't try further but I am sure I could have peaked out. Usually, though, I never drove it past 110-115 on motorway and I took good care of it (regular check-ups, etc).
Not an advisable thing to do on a Mehran because it doesnt have a lot of stability and good brakes.