Some measure the cam at 271 @ .050, mine measured 272 @ .050, that makes the math more simple.

But, for Strait up at a 106 ICL

--------open------ close-------
int: 30* BTDC, 62* ABDC
exh: 62* BBDC, 30* ATDC


But, as MP suggests a 104 ICL

-------open------ close-------
int: 32* BTDC, 60* ABDC
exh: 64* BBDC, 28* ATDC


But, Racers in the know, set it around a 100 ICL

-------open------ close-------
int: 36* BTDC, 56* ABDC
exh: 68* BBDC, 24* ATDC


See how Strait up works with symmetrical cams. With the Piston ATDC, the cams intake and exhaust lobes are centered as well between Max lift so the opening and closing numbers events match but on opposite sides of the pistons TDC