What is the best RPM range for the 4.3 liter V8?

[ppine]

By 2006 the 430sc came with a 6 speed transmission and a top speed around 140 mph.  That means in D for drive the car tends to loaf along at 1200-1500 rpms a lot of the time unless it is on the highway.   Lately I have been using the alternate manual shift pattern to keep the car around 2000 rpms or more.   I am getting around 20 mpg.   Peak torque is somewhere around 3,000 rpms, but peak horsepower is way out around 5,600 rpms.  What rpm range do you like to run in ?  I would to hear from people that have owned these cars for awhile.  I am new at this and have only had the 430 for a couple of weeks.  I don't like the idea of lugging the engine, nor do I need to wind it up for maximum performance.  What do you say?

[rc1047]

Personally I wouldn’t worry about lugging the engine. The automatic transmission will downshift & prevent any lugging. I get 25-29mpg on the highway. Also, running premium is a waste of money (in case you’re interested) I run mid grade. I’m at 5000’ elevation, so I could probably run 87 instead of 89. The engine never pings. I have 140,000 miles on my SC430. It runs like new. Burns no oil. The engine is bulletproof. 

[ppine]

Hi RC. Thanks for your response.  At around 40-45 mph the car tends to run at around 1,300 rpms in Drive.  I think that is too low. 

What mods have you made to get to 29 mpg?

I think quality cars should run on the fuel they were designed for as in 91 octane. I have run other grades of fuel before, but if I was trying to save money, I would be driving a Toyota instead of a 430sc.

[ppine]

I read the owner's manual last night. It seems to agree with RC's idea not to worry about lugging the engine.  There are no suggestions for desirable rpm ranges.  Just the note that for economy run the car in Drive.