They could be woken up pretty easily-camel humps, a moderate cam, & a single plane aluminum intake were a good start. The bored out 283 in my brother's CJ doesn't do bad (aluminum heads, 302 CI, headers, VV Edelbrock carb)-any more motor he would start breaking stuff... (friends in the day had experience in this area with a CJ-7, a built 401 out of an Ambassador or Matador?-CRUNCH went the driveshafts, transmission, axles...).The 283 used a small bore which limited breathing due to small valves. It was not a good engine.