71 Roadrunner base motor was the 383/4 with the 340/4 optional. 1974 the 360/4 caught up
V8-360 4-bbl 4.00 x 3.58 8.4:1 245 @ 4800 320 @ 3600 45-65
V8-400 2-bbl 4.34 x 3.38 8.2:1 185 @ 4000 315 @ 2400 45-65
V8-400 4-bbl 4.34 x 3.38 8.2:1 205 @ 4400 310 @ 2400 45-65
V8-400 4-bbl 4.34 x 3.38 8.2:1 250 @ 4800 330 @ 3400 45-65
V8-440 4-bbl 4.32 x 3.75 8.2:1 230 @ 3600 350 @ 3200