Aluminum vs, Cast Iron Block

[undy]

Originally Posted by StangerX

An aluminum block is a horsepower sponge you lose atleast 10% horsepower
by useing one.

...couldn't be further from the truth.

[Ant]

StangerX,

10% loss of power by using an aluminium block, is that because the aluminium conducts the heat better than cast iron, or removes heat/energy generated, so in effect an alloy motor is a heater?
I find your claim very questionable, as the efficiency of the engine is to do with design, and heat is a by product of this.

[Manowar]

[quote=Bunkie314]Manowar,

Got any spec's on how tight you thread in the freeze plugs? Do you use an NPT cut block with a NPST plug? I've got some weap issues, as if you can't tell by the question. Don't want to overtighten or go to something soft and gall. Any help you could offer? Steel to aluminum torque spec maybe?

Our plugs are 1 5/16 x 12 with o-ring. Anti-seize threads lightly and snug them without damaging o-ring.

The concerns about power loss with aluminum blocks are greatly overstated here, based on our experience. We build over a hunderd a year. We ran a 540 on Tues with the aluminum block option which is rated at 630 and it made 701 on it's best pull. Iron versions have been steadily making in the 690 range.
Factor in a 100+ lb. weight loss plus the ability to increase compression with aluminum components (thus increasing power) and you easily exceed the possible 12 or so horsepower differential across a 500 HP rated engine, iron vs aluminum.