Im thinking of replacing the Dana (1/2" pinion offset) on my car with another Dana that has stock (1 3/16") pinion offset. Will this cause me any problems ?

No

I measured it wrong. the one thats in the car now is centered. Do you think its still ok?
I have no motorplates and i have to redo the transmount. Should i try to offset the whole drivetrain?

If your present rear is centered and you are using stock motor mounts then the new rear with offset will line up better than the one you have now. I think that you will be fine. The whole tunnel in your car is offset to the passenger side.

is this a stock chassis car or tube chassis car?

this is a tube chassie with centered motor and the pinion is centered. I want to replace it with a stock 1 3/16 offset rear axle.
I can (since a dont have any motormounts) offset the motor and trans to get a better line up.
But if its ok i will center the motor and use the offset pinion rear.

How long is your driveshaft now center to center to the U joints? If my math is correct it looks like the pinion will be offset 11/16 from the trans yoke, yes? Offset(up, down, left or right) is needed to make the Ujoints rotate the needles in the cups so they don't berneild(SP)(not rotate)and ruin the joint