usafhg wrote:
This is in response to a thread that was discussing the limits of
naturally aspirated HP in a 305 c.i.d. engine.

Well, first, I must confess I don't know too much about recreational
boating engines specifically. However, there is much in common between
car and boat engines. As far as reliable operation is concerned, lets
look a moment (bear with me) at the Infiniti G35 VQ 3.5 liter 6
cylinder engine.

At what RPM? Where is peak torque?

........


Now, there are design limitations to some engines, but the naturally
aspirated 305 is capable of more than 260 HP. Using that engine block
with modern components and design tweaks, it would seem that much more
can be achieved. If not, use a different engine. Unfortunately, I
don't have specific 305 examples on the top of my mind, and I'm not
sure what some might call reliable performance either.

However, take this additional example from the 2007 SALEEN S281 3V
Coupe Mustang, which is a high quality built engine by Saleen. Running
it moderately most of the time and hot sometimes with proper
maintenance, this thing wouldn't quit on you for a couple decades or
so...

ENGINE
Type 4.6L, 3V, SOHC V-8
Bore and Stroke 3.55 x 3.54 in.
Displacement 4.6 liters, 281 cu in.
Accessory Pulleys Saleen Underdrive Pulleys
Exhaust System Saleen Stainless, 2.5 in. Variable Exhaust
Horsepower 335 bhp @ 5200 RPM
Torque 345 lb-ft @ 4500 RPM
Fuel Premium Unleaded 91 Octane
Intake Saleen Design Hi-Flow Inlet Tube and Air Box

OK... now show us where/when the Saleen Mustang will be run for extended
periods at much more than 10-15% of it's rated peak?

Now how about that lowly 305? Your 305 will deliver 200-225 hp for
hours on end and not even whimper. Try that with the Saleen.


Rob