First off I think you ought to scrap that piece of junk and sell it to me!!!!
However I do not believe that is going to work out too well. Those rifles are find shooting rifles, and I am a follower of the .270 Winchester cartridge. I read on this forum all of the time about hunters making shots out to 500-800 yards on game animals, so yes that certainly is possible. Right now I have a .270 Ackley Improved with a 1:10 twist barrel. I built this rifle for whitetail deer hunting and with 300-500 yards shot as the furthest shots that I intend to be taking at game. I was also planning a mule deer hunt out west; however....with mobility problems due to too many orbits around the sun that probably is not going to happen. Anyway I've written what I have written as some ground work for my thoughts about a 1:8 twist barrel change. You really have a very nice, "ACCURATE", vintage rifle who some people would really love to own,
in its original condition. With that said my only thought is, "do you really have a need for a rifle that shoots heavier .270 bullets??" Is there a particular reason for going this route, other than "it's because you want a rifle that shoots heavier bullets, or...you have a particular need for changing bullets from the 130-150s out of a .270?" I have had thoughts about changing the .270 Ackley Improved, 1:10 twist barrel to a 1:8 twist barrel; however, what I asked myself was do you really need to do that for what you plan to do with this rifle?? And for me the honest answer was
"NO", it's more of a trendy thing that something that I really have to have or need for what I plan to do with this rifle. I actually built two, .270 Ackleys, with 26 inch Lilja barrels on them, and "if" I were to build them again, I would build them with the 1:10 twist only because these rifles are extremely accurate and will do everything that we designed and built them for. My only suggestion to you would be that if you want to shoot heavier bullets would be to purchase a donor rifle and rebarrel the donor rifle with a .26 inch barrel, 1:8 twist barrel and chamber that donor to .270 Winchester so you can shoot heavier bullets and get the extra horsepower out of the overbore .270 with the 26 inch barrel. The only difference in cost between rebarreling what you have and purchasing a donor rifle will be the cost of the donor rifle. One last thought is that just because the rifle has been rebarreled with a new, quality barrel, it does not mean it will be accurate, hopefully it will but not necessarily so. One-inch groups at 200 yards is nothing to complain about. Hope this helps answer your question, and good luck with any route you choose to go.