Again! Shot blasted or not, No problem using them
if you know what you are doing.
Arm yourself with a surface plate, internal bore gauge,a new set of shells, plastigauge and some wet'n'dry + some patience and a small amount of intelligence = job done.
Very old, done to death subject
Most shops will tell you it can't be done
ONLY because either they couldn't be arsed or the labour could out weigh the cost of a second hand replacement head.
Go to any decent engine reconditioner or proper engineer (not fitter) and they can do it if you are prepared to pay the £££££.