Did GM make a lot of these? What percentage do you feel are cracked? Like to get one if I need to rebuild my 235--Thanks Bill
Yes, GM made a lot of the "848" heads.
All high oil-pressure car/truck 235 engines from 1956 through 1962 (and all post-1962 GM replacement heads) were "848" heads. Only the 1954/55 235s did not have the "848" heads.
Nonetheless, many "848" heads seem to have cracks, and good ones will become rarer every year. Good 235s are often kept in service. Bad-headed 235s are taken out of service. Spare heads come from out-of-service engines - which may well be out of service due to a cracked head.
If you are buying a head from someone, pay to have them test/check the head for cracks, before paying for the head (or, pay more for a pre-tested head).
