(Newbe) 273 to a 340 and tremec 5speed swap.

I would pass on the five speed swap, but go for the 340. Your'e looking at a lot of floorpan work and may also have to modify the torsion bar mounting crossmember to fit the Tremec. That's every bit as ambitious of a project as swapping in the big block you had mentioned in an earlier post. What are your goals and intended purpose of the car? It's possible to build a car that you can have a whole lot of fun with and not have to go crazy with modifying it. Oh, nice choice, too! I love a '67 barracuda notchback.