351w
My Dad always had big cars with big blocks, '66 Chrysler 383, '74 Buick Electra 455, '74 New Yorker 440, then bought a 1979 Lincoln Town Car 400. He was told it was a big block by the seller, when I told him it was a small block he was soooooooo pissed, never seen him that angry.
I bought the Buick and raced Dad in the New Yorker, I kept it in first gear, the GMs shifted out at 60 mph he kept his in auto, I won he said I cheated. Greatest race I ever had in my life!