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This is a solid post A 4340 forged crank with a 4" arm has around a 7300 rpm max safe limit providing good balance, A factory block, depending on sonic numbers and expertise in machine work and assembly have a variable that's hard to nail down <Most seem to think 600hp is getin close to the top> I see dyno sheets of 650+hp @ 7500 rpm on lots of factory blocks? Either way 7500 is exceeding the safe crank rpm in most stroker cranks, is trying to stay under the safe rpm just leaving too much on the table? Is the duration of High RPM short enough to bump up the RPMs, When they quote a safe FPM is that for continuous or intermittent use?

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I cant say what the realistic HP limit is on a stock
SB... but if I spin a engine hard I want light parts
and a good balance... I have had my 405 ci up to
9600 searching for power... it quits about 8100
but holds it. My 395ci W-2 is just short of 600hp
and I run it to 8200 also but with my better heads
on my 405(W-9 heads) I figured it would want to turn
higher to make the power... but I did sorta wimped on
the cam and didnt go to the lift I needed and maybe
short on duration but I was looking for longevity
also (spring life) but they have been holding up fine