Between May 19 and July 12, 1966, three black Orions (148669, 149673 and 149678) were handed over to the Republic of China Air Force (RoCAF) (today known as Taiwan). The RoCAF flew them for a very short period in support of a covert CIA program. All CIA P-3 missions were called off as of January 25, 1967.
After all three were returned, two were converted to EP-3B (149669 – PR32 and 149678 – PR-31). As indicated in one of the related posts, the two EP-3B arrived in Japan in 1969, providing much needed relief to the overworked Willies (EC-121M).
The third buno (149673) was converted for another (non-SIGINT) special mission. Both of the EP-3Bs flew extensively for the remainder of the Vietnam War and long afterwards. Sometime in the early 1980s PR-31 went over 20,000 flight hours, making it one of the high time P-3s in the Navy (if not the highest), followed shortly thereafter by PR-32. Both continued to fly until the late 80s when they were retired and replaced by newer converted P-3s. So the PR-32 that landed in Hainan was not the original PR-32, but the replacement. The two Bravo birds (aka Batrack) had unique backends, different from the EP-3E ARIES later flown by VQ-1 and VQ-2.
Source: From Bats to Rangers (FAIRECONRON TWO)
Updated by LCDR Bob Morrison, USN retired
Station HYPO 
19 May 2019 at 11:18
There were actually three P-3A transferred to this program (149669, 149673 and 149678). After all three were returned, two were converted to EP-3B (149669 – PR32 and 149678 – PR-31). As indicated in one of the related posts, the two EP-3B arrived in Japan in 1969, providing much needed relief to the overworked Willies (EC-121M). The third buno (149673) was converted for another (non-SIGINT) special mission. Both of the EP-3Bs flew extensively for the remainder of the Vietnam War and long afterwards. Sometime in the early 1980s PR-31 went over 20,000 flight hours, making it one of the high time P-3s in the Navy (if not the highest), followed shortly thereafter by PR-32. Both continued to fly until the late 80s when they were retired and replaced by newer converted P-3s. So the PR-32 that landed in Hainan was not the original PR-32, but the replacement. The two Bravo birds (aka Batrack) had unique backends, different from the EP-3E ARIES later flown by VQ-1 and VQ-2.
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20 May 2019 at 04:15
Pretty sure all the conversion work was done by Air America at Greenville, Texas.
It was part of E-Systems, which also built the several versions of the RC135 including the Rivet Joint, Cobra Ball, and Combat Sent.
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22 May 2019 at 02:01
Backend gear (at least the NSG part) was Ling Temco Voight (LTV) which I think later evolved into E-Systems (Guy, weigh in here!). The VHF receiver used was the G-175J, which in many ways was similar to the R-1279 (built by CEI and later W-J). In addition to the receivers, there were reel-to-reel recorders that used standard 7″ reels, and a specialized demodulator. All of this stuff was LTV and did not carry a standard JAN designator. I never encountered this gear anywhere else in the Navy, only on the EP-3B.
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22 May 2019 at 08:12
LTV ELECTRONIC Systems became E-Systems, which ran Air America
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