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red line RPM?

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yes we all know guys that SAY they run thier engines up to 7000rpm befor shifting but........
redline? thats the point were bad things are likely to start happening due to stress on the parts,in most stock small blocks thats reached at about 4000fpm of piston speed or 5900-6300rpm due to valve float with the stock hydrolic lifter cams and well worn valve springs. piston speed is figured bye knowing that 4000fpm=48000 inches per minute of piston speed, now since a piston changes direction twice in one revolution(RPM) the piston moves twice its engines stroke divided into that 48000 inches to find the redline rpm
example a 383 has a 3.75" stroke so 3.75x2=7.5" so 48000" = 6400rpm max safe piston speed if the parts are in great shape and valve float does not occur first.
example a 350 has a shorter stroke, so with that engine we get 3.5 x2=7" 48000"/7"=6857 rpm
see how it works? now you can raise the rpm level to about 4500fpm if your useing ALL racing style all forged and ballanced parts (ROD BOLTS ESPECIALLY NEED TO BE TOP QUALITY) but valve float will still in most cases limit you to the 4000fpm range (especially with a hydrolic lifter cam)
keep in mind stress is cumulative, A GOOD BALLANCE JOB CAN ADD SEVERAL HUNDRED RPM TO YOUR SAFE LIMITS) and as the valve springs age and rod bolts get older the true red line will tend to get lower your better off building an engine that efficiently build a high torque range in the 3500rpm-6500rpm range than to try pushing the engines stress limits! an engine spinning 6000rpm is under MORE THAN 4 times the stress of that same engine at 3000rpm!
here this makes it easier to figure the engines rpm limits with stock parts

http://www.prestage.com/carmath/dynochart.asp

http://www.geocities.com/z28esser/ratio.html

http://users.erols.com/srweiss/calcrpm.htm

http://users.erols.com/srweiss/calcrgr.htm

http://users.erols.com/srweiss/calcmph.htm
 
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