UlrtaDyne went out of business about 4 years ago But Harold who designed all the grinds now works at Holley as does Steve Slavik who used to work with UltraDyne so the grinds are still available Through Holley / Lunati If you know what to order
For best power between 2000-6500 I would order the -43799- TF60-TF60-08 grind , the specs are 251/251* duration @ .050, 278* duration advertised, .570/.570 lift with 1.5 rockers / .608 lift with 1.6 rockers , ground on a 108* CL
typically the 516 heads have smaller valves , but i always install hardened exhaust seats & 1.81 valves
Ther customers 440 had a stock bottom end with Speed Pro L2295F Dome pistons & 906 heads , TTi headers , M1 intake , 850 carb , 727 trans
we are upgrading to a 1050 Dom & M! 4500 intake this season & should see anoth 40+ HP gain