I had a 57 Pontiac when I got home from the army with a wheezy 347. Exhaust didn't smoke but the blow-by was horrendous! I couldn't keep oil in it so I also ran 90 weight gear oil. Big mistake! The 90 WT fumes found all the teeny holes in the firewall, sending that smell into the car....argh! That winter a buddy totaled his 59 Pontiac and I bought his low mile 389 engine/stick setup. Took months of time and many "blue trees" before the smell went away.