I'd be scared to mill the heads with that kind of lift and size of the cam.

 

While you have the heads off invest some time to clay in the piston tops to check for piston to valve clearance.At least you'll know for sure what you have,before you encounter any major parts breakage.You'll need .100"clearance to be safe on the exhaust valve and maybe .080" on the intake.

 

That cam should rip. Go big or go home. You won't miss the low end at all becuse with any 3000+ stall you won't be in the low end.

 

Good choice for a 5.3 IMO!!

 

I hope I am wrong, but I think you will be dissapointed in a cam that big. I dont think the roots/twin screw blowers work well with large cams. Be sure to post up some numbers when its done. Prove me wrong

 

I do.

This thread here gives a few details on why: https://ls1tech.com/forums/showthrea...aft+discussion

 

He's going NA.

 

this brings up a good point about an NA engine having a certain maximum amount of air it can take displace regardless of how well everything flows at a static state, but in my humble opinion I dont think he is gonna be anywhere near that point with his setup and operating range. With a smaller motor you can make up for lack of displacement with very high rpms hondas s2000 is a good example. Nascar engines get around 700-800 hp out of a NA 358 at around 8000+ rpms.

 

I have faith in this setup hopefully I wont be eating crow. We are gonna see some suprising numbers I think with the right heads 400+rwhp is more than possible from an NA 5.3 only question is where in the rpm range will it be.

 

HP will peak at 62-6400 rpm just like most all Gen IIIs do w/ the ls1/ls6/truck intake manifolds. It's enough cam to be shifted at 7600rpm but, you'd have no power at this point because of the supporting parts.

See, I can make a 220/220 110 profile peak at 6200 rpm. The same rpm that this 233/239 grind will. The only thing is, the 220/220 profile will make more torque from launch until 5000 rpm giving it the acceleration a truck will need. Where do you get that quick e.t.? From the 60'. You can make up ground by lower gears and more stall but, why not use a proper camshaft.

Again, they have the supporting parts to do so. Damn the long runner EFI intake manifolds.



I think Ed Curtis sums it up very well with this post: https://ls1tech.com/forums/showpost....0&postcount=29