What we researched for this specific generation: where an enclosure actually fits, what the factory speakers are, how the factory audio is wired, and which real builds and commercial products exist for it. Confidence badges say how well each figure is sourced — this is research, not manufacturer spec.
Body styles covered: 2-Door Coupe Utility (car-based pickup)
These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.
| Location | behind the seat, cab |
|---|---|
| Outer bounding box | Published box footprints are lower bounds on the cavity, not the cavity. Ground Shaker (labelled by Ground Shaker, 78-87 El Camino): sealed box Height 14 1/4", Length 18 1/4", Top Depth 6 1/4", Bottom Depth 21 1/4"; ported box Front Height 14 1/4", Rear Height 9", Length 42", Top Depth 6 1/4", Bottom Depth 20" (23 1/4" on the 8" version). |
| Known obstructions | Ground Shaker's 12" sealed page warns: SUBWOOFERS WITH WIDE MAGNETS/BASKETS MAY NOT FIT. |
Sizes and depths below are what research turned up for this generation. Confirm against your own vehicle before cutting or ordering — trim levels vary.
| Adapter bracket needed | unconfirmed |
|---|
| Factory amp / premium audio | no 1978-1987 El Camino factory audio source was found. |
|---|
A car-based pickup with the cab and bed in one body. EPA lists it as 'Standard Pickup Trucks' with no luggage volume (every luggage and passenger-volume field on its record reads 0), and no maker cargo figure was found. The only measured space is the Ground Shaker box footprint behind the seat. Measure your own cab before cutting wood.
Outside links. Some are commercial products, some are owner builds posted on forums — the label says which. We do not endorse any of them.
Each link opens the tool with this vehicle already selected.
Measure your own vehicle. Trim levels, factory subwoofer options, and mid-generation changes all move these numbers, and a box cut to a researched figure that does not match your truck is wasted wood. Where a badge reads Unconfirmed, treat the value as a starting point for your own measurement, not as an answer.