1971 340's True HP?

1968 Chevrolet 'Engine Packages'

307/200
327/210
327/250 'Base V-8 4-Barrel Engine'
327/275 {L-30}
302/290 {Z-28 Camaro}
350/295 {L-48} 'SS Option'
327/300 {L-30} 'Base' Corvette Engine w/special Carburetor and Exhaust
327/325 {L-79}
327/350 {L-79} Corvette w/special Carburetor and Exhaust

396/325 {L-35}
396/350 {L-34}
396/375 {L-78}
396/375 {L-78 w/L-89 Aluminum Cylinder-Head option}

427/385 {L-36}
427/390 {L-36} > 'Corvette' w/Special Exhaust
427/400 {L-68} > 'Tri-Power'
427/425 {L-72}
427/430 {L-88}
427/435 {L-71} > 'Tri-Power'

And, with the ZL-1 'All-Aluminum' {427/560} in the early-stages of development for the Corvette.