New performance Slant article in Hot Rod
Yes, it is a good one. Most interesting is the head work.
I think it's an interesting article, too, It was written to illustrate the many ways that performance can be improved by conventional hop-up methods, such as increasing displcement by boring and stroking, increasing the compression ratio, installing bigger valves and porting the head to take advantage of those valves; opening up the intake to more flow, through the use of a bigger carburetor, and optimizing exhaust flow through the use of a header, to move more exhaust, efficiently. All this is aided by the installation of a camshaft that lifts the valves further off their seats and holds them open longer.
The engine builder even went so far as to fabricate a fuel injection system; this engine was built by a knowledgeable, professional team that left no stone unturned (within reason,) in getting the absolute max out of this naturally-aspirated 225 motor.
I think, after lots of time and effort, this excellently-prepared motor made just a little over 300 horsepower.
This project was NOT a "budget-build." It represented the max you could reasonably expect from a naturally-aspirated slant six on gasoline, that had been treated to virtually all of the conventional bells and whistles we commonly use to make these things go fast...
Just a shade over 300 horsepower.
That's about 1.3 horsepower-per-cubic-inch; enough to put an A-body into the twelves.
There is, however, another train of thought that wants a little more from the leaning tower of power, and at this point, there are a couple of examples that have shown us that 300 horsepower is nowhere near the maximum potential for this engine if forced induction is utilized.
Two FABO members, Tom Wolfe and Ryan Peterson have built near-identical 225's with turbo's that each demonstrate 500+horsepower capability and do it without any exotic, state-of-the-art components nor stratospheric rpms. They are both redlined at 5,500 rpm.
Neither has a roller cam nor fuel injection. They both use 1 4bbl Holley carburetor and an automatic transmission.
Here are their videos...
[ame="https://www.youtube.com/watch?v=EAxRmoDgsdY"]Turbo charged Slant 6 11.02 @ 120.56 - YouTube[/ame] 1970 Dart 3,200 pounds
and
[ame="https://www.youtube.com/watch?v=7QzUfV8iTpQ"]Turbo Slant Six 10.74 @ 127 mph 7-19-10 - YouTube[/ame] 1966 Valiant 2,800 pounds
Those cars were both running 28 pounds of boost.
Adding a turbo to the motor appears to be good for about another 200 horsepower in this case.
That the people who built that slant six motor and spared no expense to get a little over 300 horsepower, didn't go a little further and add forced induction (supercharging or turbocharging; there's not much difference,) is really too bad, because they might have made even more power than these two private efforts.
The fact is, the astounding performance available from turbocharging a slant six is a too-well-kept secret. I think that needs to be changed.... :cheers: