I was looking at the Lunati website at the specifications for the LUN401A6 cam, and they only list the .050" valve events. I was wondering if it is possible to calculate the valve open and close events at the seat, given the lobe centerline and total durations at lash?

Would this be right?

intake duration, seat to seat: 276 degrees
intake centerline: 104

276/2 = 138 degrees

104 - 138 = -34 > 34 deg. btdc?
104 + 138 = 242 - 180 = 62 deg. atdc?

did i waste my time? lol...

Each cam grinder has there own way of listing cam specs. they like to use the .050" specs. because you will have almost usless airflow under .050" lift anyway so seat to seat timing is really not an effective specification as far as a real world perfomance standpoint ;)

You would be correct assuming a symmetrical profile. Most of the newer stuff is unsymmetrical. I think Harold says to add or subtract a few degress depending if it opening or closing on his grinds. That particular grind you have may be symm though.

i was using seat-to-seat because i'm trying to work with my DCR calculations...

Have you tried to e-mail lunati for the seat to seat timing specs just tell them you want to figure out the DCR and you need those specs to aid in your cam selection smile.gif