Hi Frank
comp says 3:91 but with 512 cubes you will be ok with 3.54
but X2 what fast68Plymouth says
As andyf says (and he should know) 236/242 is too big
but .050 is worthless for cam selection-it's for degreeing in a cam
you need seat timing
problem with comp is you get a different answer with every tech
BTW all retrofits use Johnson lifters (if I'm wrong someone say so)
get a second opinion
http://jonescams.com/street-performance/
I like Jones inverse radius flank profiles
you can have shorter seat to seat duration or a fatter cam at the same duration or somewhere in between
get your head flows
cheers
you may not end up needing the lca squeezed as much giving more vacuum (less overlap) as the inverse profile can allow the intake to close earlier with a wider lca