First, I hope you're aware that the 67-68 FB is the most popular body style now, thanks to Elenor, and that finding a car worth fixing will cost you at least $9k. The Hipo was in its last year in 1967, and production was LOW, and IIRC only 4000 or less FBs got a Hipo. The 302 didnt become technically availible until 68, you could get a standard 289 in 67 though.
HTH
--Kyle
Outside of the '65 convert. (one of which lives in my garage), the '67 F/B is my favorite body style. As for engine, I'd go for the 302. There were many made and you can find them anywhere. I even have one waiting for my next build and a third set of worked heads. But I'm in no hurry, only have 155,000 miles on this build Thank goodness for synthetic oil! On the bottom end, you can have the rods drilled for 11/32" and use ARP bolts, remove the flashing and then have them shot peened; balance the reciprocating assembly and you've got a Hipo short block, better than a Hipo really. The Hipo dampener is different but not really necessary. The heads are basically the same as non-Hipos, but you can work them too. Bigger valves, good springs, etc, a solid cam and gasket matching and the top end will be better than the Hipos. Plus you can play with intake, exhaust and ignition. And you won't be carving up a Hipo engine. The best part is that you can build an engine that will have more power. This all assumes that you don't care for originality. To get an idea of price, pick up a copy of Hemmings Motor News, there are sometimes Hipo 289s for sale (they are expensive). Hope this helps.