Via Loconotes:

"In September, IC SD40X 6071 was donated by Canadian National to
Monticello Railway Museum (Monticello, Illinois).

IC SD40X 6071 was built in 1964 as EMD 434 (29025, 5662-1). EMD 434 was
the first locomotive to be powered by the EMD 645-series diesel engine.
EMD 434 was painted in EMD's orange and white demonstrator paint scheme,
but was quickly repainted into AT&SF's blue and yellow paint scheme,
sans lettering, for evaluation and testing by the AT&SF.

EMD 434 was sold to Gulf, Mobile & Ohio and numbered GM&O 950. Sometime
after the 1972 GM&O/IC merger, GM&O 950 was repainted into ICG's orange
and white paint scheme and renumbered ICG 6071. ICG 6071 was rewired at
VMV (Paducah) in 1995. After "Gulf" was dropped from the Illinois
Central corporate name, ICG 6071 was repainted into IC's black and white
paint scheme and renumbered IC 6071."

Thats good news. A locomotive worthy of preservation.

Did this locomotive have the SD-45 style flared radiators when built? If so, when did it loose them?

I've seen a photo or two of the first GP-40, built at the same time as this locomotive, and it had the flared radiators, and even ended up with the ICG.

No. Wrong loco.

The confusion apparently sets in because there were a bunch of EMD 645-engine experimentals numbered "434". The original 434, built 1964, resembled an SD35 on a short frame (no "porches" as the later SD40's had) with three radiator fans; that's the one that ended up as GM&O 950 and ICG 6071. The radiator flares showed up on EMD 434A through 434F, later UP 3040-3045, built 1965; two later demos, 434G and 434H (UP 3046-7), built 1965, did not have these sloping radiators.

Info courtesy Diesel Locomotives: The First 50 Years by Louis A. Marre.

If memory serves, the GP-40 was wrecked and morphed into a GP-35.

DPK

Oh, so now you want to discuss the GP40 prototype? May 1965, 433A, sloped radiators, became IC 3075, rebuilt to GP35 specs and re#ed 2550.