Bizarre 617 fuel delivery begin, duration

[rocket88]

Who can solve this riddle?
Begin of delivery: 360 BTDC
end of delivery: 10 BTDC
it starts again at approx 25 ATDC, I have not verified the non compression cycle delivery

I checked the whole 360, much of it in 45 degree increments since there is no visible graduated scale , I made some of my own reference marks.

Thats right, totally kookoo. If flows freely for most of the 360 degrees.

Just installed this ip, it's from a car that ran very well.

What can be happening?

Thanks in advance

I'm not pullin' your leg.