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Cadillac 49 V8 specs: 300 ci (4.9L) 8-cylinder, 3.622 x 3.622 in (92 x 92 mm) bore and stroke, 9.5:1 compression. Rated 200 hp. Rod ratio and piston speed.
The Cadillac 49 V8 is exactly square — 3.622" bore and 3.622" stroke are the same — which splits the difference between a high-revving layout and a torque layout. The 3.622" stroke puts mean piston speed at 4,000 ft/min around 6,650 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 37.5 ci (615 cc).
9.5:1 on iron heads is in the range that usually runs on pump premium; iron holds heat, so treat it as the less forgiving side of that range.
It is one of 3 engines in the HT4100 family, the largest at 300 ci. Factory fitments include the Cadillac DeVille, Cadillac Eldorado, Cadillac Seville and 3 others.
| Displacement | 300 ci / 4.9 L |
|---|---|
| Bore | 3.622" |
| Stroke | 3.622" |
| Cylinders | 8 |
| Compression ratio | 9.5:1 |
| Bore/stroke ratio | 1 |
| Block material | aluminum |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 200 hp |
| Bore/stroke character | 1.000 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,622 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 37.5 ci |
| Static compression | 9.5:1 — in the range that usually runs on pump premium |
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