Design revisions for ’64 were minor. Even lower tailfins created a straight-through beltline, accentuating length; grilles got a body-color horizontal bar; and taillamp housings were reshaped. A new automatic heating/air-conditioning system maintained a set temperature regardless of outside conditions—a Cadillac feature ever since. More significant was a 390 bored and stroked to 429 cid, good for 340 bhp. Unit volume improved to near 166,000.