How Much Horsepower Required to Cruise Comfortably at 70 MPH?

why wouldn't the 340 be the same?? 340 and 318 have the same stroke. Did I miss something?? Is there something about the 340 you didn't tell us?? running on alcohol?? Cam so large it won't idle under 1500 rpm's????

Assuming nothing wild here, the 340 will cruise every bit as nice as the 318.