Low speed torque and driveability ?
Imo, big cube long stroke engines with mild cams deliver the best compromise. Anyone that's driven the older stock GM 455's knows what i'm talking about. Since we're talkin A bodies, i'd build a 9 to 1 low deck BB with a 4'' plus crank, iron heads, 220ish cam and the regulation bolt ons with a 2300 stall speed, 3.23 gear and have a absolute blast.......Now if mileage comes into play, that's a whole nother issue.