There are a bunch of bows that will out perform your old bow and be a heck of a lot more comfortable to shoot as a bonus. Unless you are targeting elephant, hippo, cape buffalo, etc...there is no reason at all to shoot a bow with that heavy a draw weight.
You didn't say what your draw length is but assuming its 29 inches which is the most common you can easily find a 70 pound bow that will shoot a 450 grain arrow at 280+ fps. My General is shooting a 465 grain arrow at 270 with a 30 inch draw and it is one of the slower bows for todays standards.
My guardian last year was shooting a 490 grain arrow at 270 fps.
I shot several the other day and liked the Bowtech General. It was a 70lb with 29" draw and the factory tag said it shot a 350gr arrow 301fps. I would like to hit that speed with an arrow 50-100gr heavier than the factory tested arrow. Is there something similar out there 33 in. Or shorter that can fling a hunting arrow weighing 400-450 in a 70lb draw?
There are quite a few.
Bowtechhas both of the airborns, the allegiance, and the guardian will come close.
Elite has a few though I am not up on the elite bows.
PSE has the X-force bows that will do it. The X-force dream season should do 300 - 310 at 29 inches with a 400 grain arrow. The original X-force will do another 10fps on top of that.
The Diamond marquis will come close, about 280ish.
The Mathews DXT will come close, about 280ish.
Keep in mind that if you can get a hunting weight arrow to do 270+ then you are at a great compramise speed to have exceptional arrow flight with broadheads, a good trajectory, and plenty of Ke and momentum to drive through elk and moose.