The 340 I *thought* only came in 2 barrel trim, with approx 220hp @ the crank
i dont know to much about them but when i searched skylark 340 4bbl i came accross this. could that have been a rare motor in that car?
http://washingtondc.craigslist.org/nva/car/252579024.html
1- 1967 Skylark CONVERTIBLE, factory- 340/4bbl-hipo?,