Time period of 150 octane P-47?

[billswagger]

I can't say exactly when the 150 octane was incorporated into the P-47, but mid to late '44 sounds about right.

I think the P-47 late is a fair representation of this, but there were also short leaps in improvements made through out '44 that eventually contributed to the P-47D-30. They introduced a newer supercharger which might've also been in conjuction with the new octane. The D-30 was the most widely produced variant, which tells me that maybe they had reached a platue in its developement once it was refined for the newer octanes.

The P-47M had significantly better horse power, but appart from that, they also made minor weight reductions where they could. It was intended to be a full time fighter.
I've read that eventually the D-30 variants recieved many of the upgrades of the M and were labled as D-40s.
I think there can also be a lot of confusion surrounding these varinats because they were introduced in short succession from one another.

Thats my take on it any way.

Bill