[cottonpicker14]

I am just curious what is the maximum RPM a 468 can go (based on engines specs below) before something would happen.
Right now I have the tach light set to 6000

Engine specs are
468
10.5 to 1 forged pistons
Rectangular GM heads 2.25/1.88
Cam hyraulic roller .595/.612 242/252
Holley HP950
Edelbrock RPM Airgap
4 speed
4.10 rear

 

[oger]

Which crank and rods? The rods are usually the weak point but with a hydro cam I bet the valve train will break before the bottom end.

 

[cottonpicker14]

The crank is just a stock GM which is not forged. I am not sure of the connecting rods.
Just trying to get an approximate RMP limit.
Any ideas ?

 

[hugger_sixty_nine]

I may not be totally versed in Big Blocks but I would tend to say that 6000RPM is where most stop unless they are have a bullet proof bottom end. Even then it mostly depends on your valve train and where it drops off right. Your camshaft for instance builds major torque from 5000 to 6000 RPM and drops from there, but your HP drops earlier and peaked at 4500 RPM. The 6K mark is most likey the area where you are starting to float the valves and are going to end up breaking something. Most likely Valve Train which we all know leads to a chain of events at high RPM. I myself would not be running those RPM's with a Cast Crank and 2 bolt Mains. I'd be going 4 bolt mains and Forged Crank/Rods or short shifting it at 5500 to keep my motor safe.

Its not like a small block where you can go long on revs. Besides, with all that BB torque down low and a ton of power to 5500, who needs more revs?

Just my 2 bits...

 

[phel69]

With those heads you will still be making big hp at over 4500 rpm. I agree your hyd roller is your weak link. Without stud girdles I wouldn't go past 5800-6000 max. My engine makes good hp to 6000 and starts to fall off there but my cam is a little less duration than yours and a little more lift. I also have oval port heads.Your heads should want to make their best power over 6000 rpms.I wouldn't sweat the 2 bolt mains or the crank if everything is set up right.

 

[427ss]

I would be a little concerned with the bottom end. Not knowing the history the rods could be near the end of their duty cycle. Not to mention those factory rod bolts being stretched a dozen times. Its kind of like playing with fire.

 

[frankk]

Why not take your que from what the factory engineered into these things. Generally a 5500 redline for cast crank and similar rotating parts, and 6000 redline for the forged stuff. Frank