These are two 906 OEM crankshaft pulleys https://pbase.com/9146gt/image/148879118 I purchased from Carl Thompson many moons ago. The NOS pulley belongs to my 906 engine while the other 'used' pulley will be installed in my 2.8 RSR race motor, but only if it is re-engraved with the correct MFI timing marks.

The O.D. of a 906 crank pulley is 115mm https://pbase.com/9146gt/image/38673555

Here you can see the same 906 type pulleys installed in two other Carrera 6 race engines; Ollivie's https://pbase.com/9146gt/image/35518531 and one other at Carl Thompson shop https://pbase.com/9146gt/image/31433121 ~~~ https://pbase.com/9146gt/image/31433119 ~~~ https://pbase.com/9146gt/image/31433120

The "naturally aspirated" 906 crankshaft pulleys only has timing marks while the "injected" 906E pulleys will have added degree numbers on their face. By the way, the 911, 935 type motors essentially use the very same pulley as the 906E, see here https://pbase.com/slidevalve911rsr/image/53033907

(04/2017) These are not my two 906 OEM crankshaft pulleys https://pbase.com/9146gt/image/166761554 ~~~ https://pbase.com/9146gt/image/166761555 but rather two reproductions sent as replacements for my now lost and unaccounted for 906 OEM parts https://pbase.com/9146gt/image/148879119