Yep those stinkin economy and smog days killed many a good engine. I'd also think about keeping the 352. As far has the HP I think the 300hp is pretty close. 65 was still a good year with NO emissions and HP was running wild. I show both a 2v and 4v 352 for 65 but the 2v stock for the truck. Has the engine or intake been swapped you know? With a little help you can really wake up that 352. G.