Re: Redline/Maximum Continuous Operating RPM - Packard 6 Cylinder Engines

Posted by Craig Hendrickson On 2016/2/23 12:51:05

There is anecdotal "evidence" and then there are computer programs. I agree that anecdotal is probably a good guide on older Packards (pre V-8).

I have computer derived information on my Panther that I will throw into the discussion on this thread. The first is cruising speed:

Rear gear ratio: 3.07:1
Tire diameter: 26.2in (Goodyear Eagle RS-A P225/50R17)
Desired all-day cruising speed: 75MPH.
Engine RPM: ~3,000

This is exactly what I was looking for: a freeway cruiser than I can drive anywhere, anytime at expected Interstate continuous speeds (particularly in NV, AZ, NM, TX, etc.).

Of course the Packard V-8 has a relatively over-square bore/stroke (3.5in stroke). My Panther engine has lightweight forged pistons and tapered piston pins to further reduce the recip weight.

Just for grins, I plugged the Panther numbers into a good top speed calculator I have and it comes out 145MPH+. I'll never drive it anywhere near that fast even in bursts, but it's fun to know. I'm buying "V" speed rated tires (149MPH) because of this.

Craig