Call it whatever you like. When Im building an engine I dont realy care about stock power numbers. Plain and simple. You want to dig up 15-20 year old data more power to you. But as I said before These engines where neglected and didnt get much in the form of RESEARCH AND DEVELOPMENT. The 250 I6 was basicaly the same from 1950's through to the 80's No matter what they rated the power at.
Now lets stop argueing about stock numbers and distracting this threads original purpose, witch is the POTENTIAL of 250 I6, NOT outdated power ratings for them stock.
As with any engine the max potential is not as important as the potential you need in your intended purpose.
What I mean is your not going to build a top fuel drag racing engine for your daily driver. You need to target your prefered RPM range and build to the max possible power within that range.
NOW our trucks are usually large heavy 4x4's so keeping the power down low in the RPM's is what you should be shooting for. For instance 500 HP is not going to do you any good if it comes at 5000 RPMs and you never get over 3500 RPMs. Shooting for a specific power isnt feasable either. You need to focus on the max power at the RPM range you use most.
NOW heres where it gets complicated. The GEARING in the rest of your drivetrain can change the RPM range you use.
For example take a toyota with dual x-case's with low gear sets and low gears in the diffs. Lets just put out a crazy crawl ratio of 400 to 1. To go at a walking speed you now have to run the engine at higher rpm. If thats the speed and RPM you prefer then sure build it to make the most power at 5000+ RPM.
BUT since we are also talking about fuel milage when you drive that on the street your going to be out of the engines prefered RPM range, so it makes sence to build the engine for the RPM range you USE the most.
High RPM engines are going to struggle at low RPMs, think of it as lugging your engine. Economy does not mean low power, it comes from moving your truck at the rate you want (speed) in the RPM range of the engine that is easiest for that engine to do. ALL this time I been using horse power numbers, but torque is the number you want to look for. The more torque you have in the RPM range you use the most is going to be the key.
Quote for truth... also thanks for nicely summarizing.
I'll add this...to no one specifically... I hate it when I use the word "power" generically, and someone tells me, "what you mean is 'horsepower'".
No. I don't. I mean, the seat of the pants feeling when you step on the gas. Horsepower has its uses when describing overall output or trying to convert (mathematically) to another form of energy (watts, BTUs, etc) but in my discussion, it's a useless number, because as Balzer stated, RPMs are always going to limit the "horsepower".
I think you nailed it when you talked about the lack of development with the L6s. The V6 was the nail in the L6's coffin. Smaller packaging as well as being able to be mounted sideways for FWD vehicles made it a no-brainer.
That's not to say that a V6 is either superior or inferior to an L6. The 4.3L V6 has a bigger bore and shorter stroke. Given the similar displacement to a 250ci, when you consider the bore/stroke, it's easy to see how the V6 would favor higher RPMs compared to the L6. Different engines, built for different applications.
I envision a 292 that's simply allowed to breathe better and more efficiently. The new aluminum head will address much of the issue of lack of development, as that was the biggest shortcoming of the Chevy L6s.
Re: efficiency... Take a motor, any motor. Put a race cam in it. Measure torque at say, 1500rpm with a dyno. Re-cam it with an RV cam. Perform the same test. If 1500rpm is the target working RPM, then the RV cam'd combo will be more efficient AT THAT RPM, because it'll be making more power with the same displacement.
It's all about keeping the motor happy in your intended application by maximizing the output where you need it.
My girlfriend's Tahoe made peak 'horsepower' at 5200rpm. Peak torque came in at over 3-grand.
Why?
