I believe you are right. I was there the day my dad was testing a crank scraper on his 357ci/340. Compression should have been around 12:1, W2's (unknown flow rates), don't remember who's W2 intake, solid flat tappet, Murry Jensen modified 4150 ..........610HP.........and that was in 1977 I believe. It was along time ago to remember the exact year, but no later than 1980.