Mario, From what I read from a couple sources, the prototype was on a Sherman bought from France and some work actually done there before shipping to Israel. Trying to trace IDF armor history is extremely difficult with very limited reliable sources. I have one very good source but he is very busy and spends lots of time on duty in the field...especially now. It's a shame that Latrun can't be any more helpful and I have yet to get any replies from them, either from English or my limited Hebrew.. Looks as if IDF used radials until all M-50s had been upgraded then started on 51s and it would appear that some still ran radials in 1975 when the reserve units 51s were turned in for Cents and M-48A5s. Nice thing though, that since there were no specified standard designs and shops doing the work as they came in, some little variances in stowage boxes are kosher for 50 & 51s.