[supergonzo]

RAIV valve cover gaskets are the same as any other valve cover gaskets. The rockers are 1.65 ratio stock, but they were stamped steel and not any bigger than 1.50 ratio rockers. Only Aftermarket Roller Rockers need 2 valve cover gaskets to fit.

To add one more thing to Mike Noun's point about the 455SD motor in 1973-1974. Most performance cars with lowered compression and added emissions at this time were solid mid-high 15 second cars. The 455SD was burdened with the same problem, but was running at least 2 seconds faster than the competition in a 4000lb car!! That is really almost unbelieveble. Too bad it wasn't made in 1970 with high compression & less emission garbage, with an open hood scoop.....it probably would have been considered the ultimate muscle car mass produced engine.