1973 340, want more power.

From what I have read in the thread the OP wants a street friendly car that will push him back in the seat and run in the 12's occasionally at the track, isn't that what most want......staying with his 340 an 8.0CR motor thats (if its in good shape) around 240hp in a car that weighs around 3300+? is at best a 14.0 sec car with it tuned good and not spinning itself to death on the leave. To get in the 12.9's is going to need around 300hp, mid 12's approx 345hp.

One way forward I can see is if your going to keep the bottom end together (8:1), is it will need some good heads, IMM iron or Eddies, something that will flow well at .450>.480" around 250cfm, (thats where its all at), top that off with an rpm intake, hdrs, at least a 750>800 carb to feed the heads, a good tune and high 12's are possible, it can be done on low CR. 3.91's with a tight 2500>2800 stall and some sticky's out back, good rear springs/shocks and perhaps an adjustable snubber with 1" gap to floor (which most will say is old tech) but it still works!. That of course is 1 way, you could simply drop in a 375hp crate motor at $4700 or similar. from summit, as has been suggested....job done.