'75 A model 8.25 worth upgrading or leave as is?

I picked up a 8.25 rear end out of a '75 dart from my local pick your part.The tag on the cover says 2.45 ratio.I'm want to install the diff into my '69 dart,but since the ratio in the '69 dart are lower compared to the taller '75 gears it's gonna bog down the /6. So pretty much I just wanted to take care of it before it goes in.
My plan's in the future is to install a V8 in the '69.
Street/Strip 3.55 gears
Richmond Gear posi unit.(Peg legging get's boring real quick)
Is it worth investing or do I leave as is?

Frank