This is the route I took in my ‘71 searching for more fun... and torque. I had a 2.7 crank and rods so that helped the decision. I went with Biral cylinders bored to 85mm and new 9.5 pistons, which I think are more like 9:1 in use and E cams. Result is a more revvy engine with gobs of torque, but not a high rpm screamer since I kept the small port heads.