> Frank;
>
> -Even with the steel forged rods & crank I personally wouldn't turn a
> 289 past 7K. Don't remember the exact specs of the "K" motors right
> now.Personally, I feel consistent excursions past that RPM without
> 4-bolt mains on the center caps is risky.
Risky, we are talking hot rodding here right? I assure you that lots of hot
rodded 289s turn post 7000 RPM without failure. BTW, the 215 is a 2-bolt
main motor.
> Any engine that's "over-square" (like
> the 289 with it's stock 4.00" bore & 2.87" stroke) has some inherent
> defects from a strictly-Physics standpoint to overcome.Can't remember
> it in detail now,but I fuzzily recall it had to do with stroke, piston
> & rod weight, crank strength, acceleration and de-acceleration of the
> whole assembly etc., vs. any given HP & torque output you get at a
> specific RPM.
>
What about the Boss 302 (4 inch bore, 3 inch stroke)? Those fortunate few
who own these motors would tell you that they do quite well in the 6000 to
8500 range. The main reason why Boss can do this because it breaths so
well. You can bolt on aftermarket heads on your 289 that breath about as
well. True, the Boss has 4-bolt mains and nicer rods than the regular 302
but you can approach the bottom end strength of the Boss with a regular old
302 and modified "off the shelf" rods. Is it risky, well... yes, sure it is
but we're talking about a Hot Rod motor right? If it isn't built right or
you push it a bit too much or you don't pay attention to the warning signs
she's gonna blow but it isn't any more risky than 9000 with a 215.
Frank Marrone MK I Tiger B9471116
marrone@wco.com 1966 LTD
Series I Alpine (2.3L powered by Ford)
Yamaha Seca 900
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