So, the heads are 429, what is the casting..D0---? or D3---? non adjustable cast iron or stamped rockers?...screw in rocker studs or pedestal style with bolts?... If memory serves, 1973 '9er's went with the pedestal style rockers...there are roller kits for those as well...I think they used the large sparkplugs for all
the '9er's...sounds like it'll be a cool ride when it's completed...Cheers!