I have a LOT of respect for the modern LS platform, it's an extremely versatile and well-proven platform. That said, it seems like the old reliable big block has become the red-headed bastard step-child around here.
Here's an interesting little combination to consider;
Very basic 496, naturally aspirated and runs on pump gas
400 Turbo, tight 10" converter
3.36 gears
3600 lb race weight
Runs 10.70's @ 125 in full street trim with a best of 10.59 @ 127+
Has been together for ~6 years and has logged 14K trouble-free miles so far.
The owner just took a
week long 2600+ mile road trip with it. The only problem encountered was a fouled set of plugs from a bad batch of gas.
The ONLY "minus" is the car gets ~12 mpg at highway speeds (turning ~3K rpm). I'm sure an overdrive and further refining the 850 Holley would improve those numbers significantly. Would it ever equal the fuel mileage of a modern LS with EFI?--of course not, it's ridiculous to even ask that question.
That said, how long would it take to recover the cost of a $10K-$15K (or more) LS swap vs. a $7800.00 bolt-in engine?
Let's do a little math.
Let's assume you tune the big block to 15 mpg (well within reach) and the LS gets 20 mpg. That's 5 mpg difference--lets say you drive 5K miles a year (generous estimate IMO since few [if any] of these cars are people's daily drivers). We'll estimate roughly $3.00/gallon for 92 octane fuel. That's 333 gallons of fuel vs. 250 for a difference of 83 gallons of fuel a year. That's $250.00 a year saved in fuel. The difference between a $15K engine and an $8K engine is $7K. At that rate, it would take 28 <span style="font-weight: bold">years</span> to recover the difference in investment. Sorry, that dog won't hunt.
Again, I have tremendous respect for the LS platform, but trying to directly compare it to a big block is the quintessential "apples to oranges" comparison. Show me a cost-effective naturally aspirated LS that can make over 600 lb.ft at 3000 rpm or less and 600+ HP <6000 rpm...NOT gonn'a happen. Conversely, show me a cost-effective 600 HP big block that knocks down 20 mpg...I'm not going to hold my breath on that one either.
If I thought Ken would take me up on it, I'd offer to build him a 600+/600+ big block for this car AT COST--FREE LABOR on my end, just the cost of parts & machine work, but I know that won't happen. Ken is a die-hard LS fan now, and I support his choice 101%--it's HIS car, he should build it the way HE wants and however it makes HIM happy.
That said, can we <span style="font-weight: bold"><span style="font-style: italic"><span style="text-decoration: underline">PLEASE</span></span></span> stop trying to compare an LS to a big block? They're two totally different animals with their own distinct characteristics.
Both have earned and are worthy of their respect.
p.s. the guy with the `Vette mentioned above also owns a late model Z06 `Vette with a 402/F1R blower--the following is a
direct quote:
<span style="font-style: italic">"Thanks Del! I wasn't too worried about it. It's been a very reliable car since I built it. Now my Z06 with the 402/F1R, I wouldn't drive that sucker more then 200 miles away from home which is where my free towing range ends.
It's messed up when you trust your 45 year old car to drive cross country way more then you trust a 2002. Lol"</span>