Engine performance

[1739T]

Found this on an RV-7 homebuilders site. Here's some of his thinking behind chosing an engine. I this guy right? Is this true?

.....Looking at all options available, all companies available, all commentary available, specs, weights, reliability predictions, installation complexity, engine mount availability, and on and on and on, the correct choice for me seemed to be a late model Subaru EJ25 motor. This is a 2500cc four cylinder, opposed, water cooled, EFI, overhead cam, four valve per cylinder, extremely reliable, modern engine. The Subaru is also lighter, quieter, and has much less vibration than the IO-360. It's probably not far from the motor that Lycoming would have come up with if they had an engine design department. The EJ25 makes 165HP in stock form and is well suited to the addition of a magic little device called a turbocharger.

The good 'ol $32k 200 horse Lycoming can only put out 75% power = 150HP (at sea level). At 12,000 feet there is 40% less oxygen and, you guessed it, 40% less horsepower = 90HP out of the Lyc - yikes $32k for 90 horsepower!

[skid]

For starters the IO360 puts out 200 hp at sea level, is ok for continuous use, but most prudent people cruise at 75%(150 hp). It will maintain 75% to about 8500 feet. And this is about 2500 rpm. I'm not familiar with the Subaru, but 2500cc's is 152 cubic inches. 1 hp/cubic inch is quite a bit. The horsepower rating is probably at 5500 rpm or more requireing a gear drive that WILL soak up some power to drive. Cruising that motor at 4000 rpm is probably be no more than 75% either, or 123 hp at best. And it will lose power at altitude like any other naturally asperated engine. While it probably goes 150,000 mile in a car, it is doing it at 2500 rpm, not 4000 or 5500 for the full 165. You are going to spend almost as much for a good automotive conversion as buying a new Lycoming at Vans discount price or buying a good low time first run. Many of the gear reductions on the homebuilt market are quite good but often have a life of 7-800 hours. Most automotive installations end up being as heavy or heavier than a good Lycoming,much more complex, and have mediocre performance.
A local spray pilot replaced a 260 lycoming with a 460 ford with a gear drive and logged over 1000 hours of spray time with it quite successfully. It performed very similar to the 260 and was reliable and smooth. Both engine and drive were shot at 1000 hours, but could have been rebuilt for 1/2 of the lycoming he pulled out that had you guessed it almost 2000 hours. He probably lost the cost of the overhaul in spray business the first year sorting out little things when he converted it. But he did it for the challenge, not the economy of it which was about the same.
I think these kind of things are great if you want a challenge and are very ambitous. Experimenters broaden everyones knowledge base and often get the big manufaturers off their duff to design someting new, like slick's electronic ignition. Just beware of kit manufacturers claims as this is the type of product that seems too good to be true and it usually is.