Mopar fans, get ready! I’m excited to share my journey of breathing new life into my 1969 Plymouth Satellite by swapping in a modern 5.7L Hemi engine and A727 transmission. After sitting idle for over a decade, this Satellite, originally a 318/904 car with column shift and a 741 case 8 ¾ rear end, was begging for an upgrade. Despite being an AC car with the larger 26” radiator core support (AC components now removed), and showing typical rust for its age (addressed some time ago with a decent paint job), its solid frame and body panels made it an ideal candidate for a heart transplant.
Interestingly, somewhere in its past, the Satellite gained a ’69 Coronet front clip after a front-end collision. Personally, I prefer the Coronet front, although it does lead to some confused looks at car shows! The bumblebee stripe, while not to my taste and incorrect for this model (or even a Super Bee replica), is staying for now as the paint is in good condition. A wrap might be in its future to address that. All these factors combined made this ’69 Satellite the perfect project car for a modern Hemi conversion. If you’re considering a similar project for a ’68 Plymouth GTX or any B-body Mopar from this era, many of the steps and considerations will be directly applicable. While this article details a ’69 Satellite, owners of ’68 Plymouth GTX models contemplating an OBD2 conversion will find valuable insights here.
Pre-Swap Planning and Parts Considerations for OBD2 Compatibility
Embarking on this Hemi swap, the biggest hurdle was deciding on the optimal combination of engine, transmission, ECU (Engine Control Unit), and wiring harness. The choice between used and new components was also significant. To minimize potential compatibility issues and streamline the initial setup, I opted for all-new parts.
For the engine, I selected a Mopar Performance 5.7L Crate Engine, complete with a factory controller and wiring harness. Needing a new transmission anyway (as my original 904 wasn’t going to cut it with the Hemi), I chose a new A727 TCI transmission known for its robustness.
Early in the planning, Holley’s B Body Gen 3 Hemi Swap components became central to the build. Their extensive range of swap parts is incredibly comprehensive. Crucially, everything from Holley fit perfectly. The engine and transmission installation was seamless, and the headers and exhaust aligned perfectly, requiring no modifications or hammering – a testament to well-engineered swap components. This is especially relevant if you are thinking about an OBD2 swap for a ’68 Plymouth GTX, as component fitment is critical in these classic chassis.
Another indispensable resource was Bouchillon Performance Engineering. They specialize in those crucial, often hard-to-find parts that bridge the gap between modern components and classic car systems. Randy Bouchillon’s expertise in Gen 3 Hemi swaps is unparalleled, arguably exceeding even Holley’s in specific areas. He is a wealth of knowledge and readily offers advice. Bouchillon Performance provided several essential, high-quality components for my build.
The entire project spanned five months, primarily due to parts delays during the Covid-19 pandemic. Without these delays, the swap could realistically have been completed in around four weeks, highlighting the importance of parts availability in project timelines.
Here are some invaluable resources I utilized throughout the swap:
- Holley Gen 3 Hemi Swap Components for 1966-74 B-Body Mopars
- DIY Hemi Swap Guides and Parts
- Bouchillon Performance Engineering – Classic Mopar Swap Specialists
- Moparts Forum Hemi Swap Discussion
- MotorTrend: Will a Gen III Hemi Fit? Project Measured
- Allpar: Modern Mopar 5.7L Hemi Magnum V8 Engines
- Dodge Garage: Gen III Hemi Engine Quick Reference Guide
Detailed Parts List for a 5.7L Hemi OBD2 Swap in a B-Body Mopar
The following is a comprehensive list of every part used in this Hemi swap, excluding common fasteners like screws, nuts, and bolts. Where possible, part numbers and the reason for each part’s inclusion are noted. All labor, custom engineering, and fabrication were expertly handled by David Gibson of Gibson Engine Development in Austin, TX. This parts list provides a solid foundation for anyone considering a similar OBD2 Hemi swap, whether for a ’69 Satellite or a ’68 Plymouth GTX.
Key Notes on the Engine Swap and OBD2 System Integration
Initially, sourcing a used 5.7L Hemi from a salvage yard was considered, but reliable sources in the Austin area were limited. The preference was for a recently salvaged engine over one that had been sitting in storage for an extended period. Companies like Cleveland Performance and MARS LS Swap, known for their comprehensive swap packages with run-tested engines, were also evaluated. While their low-mileage swap kits were competitively priced compared to a new Mopar Performance crate engine, the decision leaned towards the peace of mind and warranty of a new crate engine.
The Mopar Performance crate engine kit is widely available; shopping around is recommended to secure the best price. Mine was sourced from “Frog” at moparproshop.com, although the drop-shipping fee was a somewhat hefty $450.
Upon installation, the engine started immediately, and all systems functioned as expected. The ECM was strategically located under the dashboard rather than in the engine bay for a cleaner look and better protection. A Dakota Digital Gauge Cluster was chosen, and the ECM communicates flawlessly with it. Importantly for OBD2 functionality, the Dakota Digital BIM-01-2 OBD-II/CAN module is necessary for the gauges to receive tachometer and oil pressure signals. This requirement is reportedly linked to Mopar’s efforts to limit aftermarket ECU tuning. This OBD2 integration is a crucial aspect for modern diagnostics and monitoring, and is equally relevant for a ’68 Plymouth Gtx Obd2 conversion.
The crate engine is shipped with oil, but the oil pan must be swapped. If you cannot salvage the initial oil, you’ll need approximately 7 additional quarts for the new pan. To enhance the engine bay aesthetics, 6.4L engine covers were adapted, and the removed AC system was replaced with a blanking plate from Vintage Air for a cleaner engine bay.
Transmission and Driveline Upgrades for Hemi Power
Upgrading from the original 904 to a more robust 727 transmission added a layer of complexity to the swap. A new column shifter cable was required, and ididit was the only identified vendor producing a compatible cable. For the kickdown mechanism, Bouchillon Performance provided an expertly engineered throttle pressure system assembly, although it represents a significant investment.
This Hemi swap project successfully brought modern power and OBD2 diagnostics to a classic 1969 Plymouth Satellite. The lessons learned and parts detailed here are valuable for anyone undertaking a similar conversion, including those considering an OBD2 Hemi swap for a ’68 Plymouth GTX or other classic Mopar B-bodies.
Happy swapping!
