No, Pro-M sells a kit that will allow you to use the old style computer, I think it's around $500.
The computer you have now will work fine with a 351 with a chip or a tweecer, which would be good to have with an old style computer too. The old computer's code was writen for 302 cid. too. With a tweecer, you can tell it what displacement motor you're running just by changing one line, IIRC.
If you don't go with too small of lobe seperation on your cam, the motor will probably run ok with stock computer. It's not much different than putting a 331 or 347 stroker in.