Packard V-8 Performance

What would the compression ratio be if you used "whatever" cylinder heads you wanted for your Packard V-8?

All percentage change are relative to the baseline for that CID. For example, putting a 1956 cylinder head on a 1955 352 would change the combustion volume* from 96CC to 85CC and the compression ratio from 8.5:1 to 9.5:1. The power would be increased by approximately 6% due to the increase in C.R. alone. The actual power gain would be even more because the 1956 Heads have a larger intake valve. See below for the effect of that change alone.

*Combustion volume is chamber volume plus head gasket thickness minus deck clearance volume.

Carburetor Performance

Bolting on a bigger (within reason) carburetor is a sure way to gain horsepower but not necessarily torque or driveability. All Packard V-8 4bbl intake manifolds are identical, but 4 different carburetors were fitted, each with a different flow capacity (CFM). Also, a new Edelbrock Performer (old Carter AFB style) carb may be fitted, but this requires either an adapter (OK) or machining the intake (best). In any case, what can you expect if you swap carbs? The chart below uses a 1955 352 CID Patrician/400 engine as the baseline. All power increases are relative to its stock carb (Rochestor 4GC-7007230).

Camshafts

The last "bolt-on" component to be considered in this analysis is the camshaft. Packard had 2 different camshafts, one for 1955 (P/N 440786) and one for 1956 (P/N 6480581). At that time, aftermarket camshaft maker Ed Iskenderian made "hotter" cam grinds available, the most popular of which was his E-2 profile. To keep things simple, we'll also sim a somewhat more radical camshaft from Craig's Panther Project: Again, the baseline engine is the 1955 352CID Patrician/400 engine which used originally used the 440786 cam.

Note that ACTUALLY putting the Isky or Lazer cam in a completely stock engine is foolish. The engine and related components MUST match the camshaft grind to be effective!