The standard engine as fitted to the "Vanguard" and also in lower compression version to all those super reliable TE20 Ferguson tractors is/was a lovely engine. Just needed a bit of servicing.
IMHO much better made than early Vauxhall stuff. In fact precision is not a word that come to mind for those. Horrible tappet arrangments often.
Stick with your Vanguard engine. It will still be going after all the old Vauxhall engines are Toyotas.