Plymouth GTX Engines by Year

The GTX was Plymouth's premium mid-size muscle car, with a 440 as its standard engine and the 426 Street Hemi as the option. It was its own model from 1967 to 1971; from 1972 the GTX name continued as a 440 package on the Road Runner, listed on the Road Runner page.

Pick a year to see every engine offered that model year, with its code, rated horsepower and the trims it came in. Each engine links to its full specs.

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1967–1971: 1967 · 1968 · 1969 · 1970 · 1971

1967–1971

Every GTX came with a big block. The 440 Six Barrel, with three two-barrel carburetors, joined the list for 1970. The 1971 ratings are gross, with net figures in the notes where published.

1967 GTX engines

Engine	Rated	Offered in
426 V8	425 hp gross	GTX (optional)
440 V8	375 hp gross	GTX (standard)

1968 GTX engines

Engine	Rated	Offered in
426 V8	425 hp gross	GTX (optional)
440 V8	375 hp gross	GTX (standard)

1969 GTX engines

Engine	Rated	Offered in
426 V8	425 hp gross	GTX (optional)
440 V8	375 hp gross	GTX (standard)

1970 GTX engines

Engine	Rated	Offered in
426 V8	425 hp gross	GTX (optional)
440 V8	375 hp gross	GTX (standard)
440 V8 Six Barrel, three two-barrel carburetors.	390 hp gross	GTX (optional)

1971 GTX engines

Engine	Rated	Offered in
426 V8 350 hp net.	425 hp gross	GTX (optional)
440 V8 305 hp net.	370 hp gross	GTX (standard)
440 V8 Six Barrel. 330 hp net.	385 hp gross	GTX (optional)

Working on one of these engines?

• Engine displacement from bore and stroke
• Static and dynamic compression ratio
• Which camshaft for your build
• What size carburetor
• Horsepower to torque at any RPM
• Torque converter stall speed

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