I don't see why not. I have plans to do the 5.0 efi thing, but I dunno if I should get the 28/50 oz balancer so I can use it on the 289 or just wait and get a regular 50 oz for the 5.0.
But yea, I'd go for it, I've pulled them on other cars before. Not bad really but I'd do it now while it's all apart and get it over with.
I run a Paxton on my 289 in a 66. Last weekend at the track I saw a guy launch in his fox body with a supercharger installed. Guess what the supercharger and crank pulley was bolted to? Yup, a stock balancer. Before the 60 ft line we all saw a stutter and from under the car rolls a black hunk of metal, we thought it was an alternator. The balancer broke in the middle. The crank through bolt was still bolted to the crank with the center of the balancer. So, this week I ordered a Summit SFI balancer. It's a 28 oz imbalance, and am also planning a 5.0 swap in the future so I odered the 50 oz imbalance adapter too. I've been running the supercharger on my 40 year old balancer for 2.5 years and no problems. After I saw that at the track I'm not taking any chances. Good luck.
If you plan on racing, I'd definitely would change it. If you just run around the streets, then I wouldn't unless its showing signs of wear. I can think of alot of things I could buy with those dollars, and if your budget is like most of us, its a matter of priorities.