chansey, the U.K. has heaps of the 1004 heads for low coins, the engine was fitted into CAT, KOMATSU and near everything else in the power class, the JCB 1700B is not known on our rock, its some U.S. spec' thing but the engine is an easy item to sort, if its had water issues check the bottom of the cylinder bores for score marks? if you are still in a jamb to find this item I could post a few phone No's etc but its U.K. supply.
tctractors