When you're choosing parts for a marine engines propulsion setup, the buying decision often splits into two very different jobs: replacing a worn component or replacing the whole engine. The DF100 inboard motor mounts and the MerCruiser 5.7L 350 V8 reman inboard engine sit at opposite ends of that spectrum, and the right pick depends on what your boat actually needs. One is a focused repair part; the other is the main power plant for a full swap.
Quick verdict
If the existing engine stays in the boat and the mounts need replacing, the DF100 pair is the focused repair at $119.95. If you need the main engine itself, the MerCruiser reman is the complete power-plant route at $4,999.00. The wide price spread makes the choice fairly clear once you know the scope of the job.
At a glance
| Consideration | DF100 Motor Mount Pair | MerCruiser Reman Engine |
|---|---|---|
| Price | USD 119.95 | USD 4,999.00 |
| Condition | New | Used |
| What you get | Pair of DF100 mounts with aluminum base and elastomer element | Remanufactured 5.7L 350 V8 inboard engine, fresh water, drop-in ready |
| Key details | 5/8-18 stud, 4-inch overall height, 4-point mounting up to 850 lb | RH rotation, bell housing stays with engine, transmission removed and not included |
Where each option wins
The DF100 pair wins when the repair is limited to the mounting side. It uses cast aluminum alloy construction and an oil- and fuel-resistant elastomer element, with zinc dichromate plated steel parts for corrosion resistance. That makes it a sensible match when the engine block itself is staying put.
The MerCruiser reman wins when you need the propulsion engine itself, not just a component. This is the option that provides the core power plant for an inboard replacement. In a marine engines propulsion project that calls for a full engine replacement, this is the route that covers the main unit.
Product notes
DF100 Inboard Motor Mounts Pair
The DF100 pair is a new set of motor mounts that targets the mounting side of an inboard engine. The cast aluminum base and oil- and fuel-resistant elastomer element are built to absorb vibration, and the zinc dichromate plated steel parts add corrosion resistance. With a 4-inch overall height, 1-7/8-inch base-to-rim height, 4-inch center on bolts, 5-inch length, and a 5/8-18 stud, the dimensions suit a 4-point mounting arrangement up to 850 pounds. The limitation is scope: this listing is for the pair of mounts only, not the engine they support. If the engine block is sound and the mounts are the problem, this component-level purchase fits the job without moving into engine replacement territory.
MerCruiser Marine 5.7L 350 V8 Reman Inboard Engine
This listing covers the whole engine rather than a mounting component. It's a used remanufactured MerCruiser 5.7L 350 V8 inboard engine with fresh-water history, described as running great and drop-in ready. The rotation is right-hand, the bell housing stays with the engine, and the transmission has been removed and is not included in the sale. The reason to choose it is the completeness of the package for an engine swap: you get the main power plant with the bell housing still attached. The limitation is the used condition and the missing transmission, which means the rest of the driveline has to account for that. It's the more extensive purchase, but it addresses a much larger job.
Final choice by use case
Go with the DF100 motor mounts when you're repairing a boat that already has a functioning engine and you need mounts for the mounting side. The mounts cover the specific component they're designed for, without pulling in a whole engine replacement.
Go with the MerCruiser reman engine when the job calls for the inboard engine itself rather than a mount. This is the route for a full propulsion replacement, where the package includes the core power plant. It addresses a much larger job than a mount.
