My grandfather recently fell severely ill, and as a way of keeping his passion for cars alive, my grandmother gifted me his 1965 Mustang. I’ve taken this to heart and have been diving deep into learning everything I can about classic Mustangs and what it would take to restore his car.
The car originally came with an inline-6 engine. From what I’ve gathered, it was likely either the 170 or 200 cubic inch Thriftpower I6, which were fitted in ‘65 Mustangs. However, there’s a complication — the VIN (chassis) code was altered when the car was imported into Brazil, and unfortunately, the engine code (which indicates the original engine type) is missing. That part of the car’s history was lost.
Considering the car was bought in 1989 — nearly 25 years after it was manufactured — anything could have happened to it in that time. When I looked at the current engine, it didn’t match what I expected from typical Mustang inline-6s. Most notably, the intake and exhaust are on opposite sides, which is not the case with the original Thriftpower I6, where they’re on the same side of the block.
I brought this up on the Vintage Mustang Forums, and someone pointed out that the engine doesn’t match the original inline-6 engines used in 1965 Mustangs. After doing some research, I now suspect it might actually be a Willys BF-184 — a Brazilian inline-6 developed from the old Willys engines and later adapted by Ford in the early 1970s. This engine was used in the Brazilian Ford Maverick as a cost-saving measurement. Despite its roots in 1930s designs, Ford modified the BF-184 to fit the Maverick, spending over a year reworking it — including changes to compression, exhaust routing, and even creating a unique external cooling hose to fix persistent head gasket issues.
Since I’m located in Brazil, this sounds like a real possibility. I don't want to say this with too much certainty since it might cause confirmation bias or premature closure. I’m reaching out here hoping someone with more experience can help me with identifying the engine and giving me more insight into its features. Maybe it's some sort of frankenstein?
Any information, insights, or suggestions for identifying this engine would mean a lot. Thank you all so much!
Here's a LINK to all of the pictures.
The car originally came with an inline-6 engine. From what I’ve gathered, it was likely either the 170 or 200 cubic inch Thriftpower I6, which were fitted in ‘65 Mustangs. However, there’s a complication — the VIN (chassis) code was altered when the car was imported into Brazil, and unfortunately, the engine code (which indicates the original engine type) is missing. That part of the car’s history was lost.
Considering the car was bought in 1989 — nearly 25 years after it was manufactured — anything could have happened to it in that time. When I looked at the current engine, it didn’t match what I expected from typical Mustang inline-6s. Most notably, the intake and exhaust are on opposite sides, which is not the case with the original Thriftpower I6, where they’re on the same side of the block.
I brought this up on the Vintage Mustang Forums, and someone pointed out that the engine doesn’t match the original inline-6 engines used in 1965 Mustangs. After doing some research, I now suspect it might actually be a Willys BF-184 — a Brazilian inline-6 developed from the old Willys engines and later adapted by Ford in the early 1970s. This engine was used in the Brazilian Ford Maverick as a cost-saving measurement. Despite its roots in 1930s designs, Ford modified the BF-184 to fit the Maverick, spending over a year reworking it — including changes to compression, exhaust routing, and even creating a unique external cooling hose to fix persistent head gasket issues.
Since I’m located in Brazil, this sounds like a real possibility. I don't want to say this with too much certainty since it might cause confirmation bias or premature closure. I’m reaching out here hoping someone with more experience can help me with identifying the engine and giving me more insight into its features. Maybe it's some sort of frankenstein?
Any information, insights, or suggestions for identifying this engine would mean a lot. Thank you all so much!
Here's a LINK to all of the pictures.
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