No arguments, you may not see peak engine performance at that rpm though.

 

As far as I know, all of the cranks are the same material, so you should be fine there.

I wouldn't worry much about the tach. After setting it up with LS1 Edit, your shifts will take care of themselves. I have mine set to shift at 6600 rpm and I log a lot of my dragstrip runs. Every shift is dead-nuts on at 6600 rpm!

I would think 7000 rpm should be the absolute MAX. I don't know what the stroke/rod relationship does for the RPM potential. The 5.3 is the same stroke, but uses a longer rod I believe, than the LS1. I don't know if that's good or bad for revving higher; it sounds like he is saying it's good.

I keep my rev limiter at 6800.

 

I'll try and explain what I remember reading somewhere about longer rods.

The longer rod will not be in as much of an angle on at 90* and 270* crank position. SInce the rod is at less of an angle in the crankcase the piston sees less side to side movement/pressure in the cylinder

The shorter rod sees more of an angle at those crank positions, creating more stress on the piston, rod and crank.

It makes sense to me, but I don't know if I explained it the way it makes sense to me. One of those things if ya know what I mean.

Are there any other truck guys out there spinning the 5.3 above 6k rpm?

Of course you would have to get a bigger cam to allow for more revs, bigger heads would help to obviously, but all this aside ... surely I won't be the first .. or I'm not the first to want to spin the motor this high.

 

Are people honestly spinning these motors to 6500rpm and above RELIABLY ???...if that's the really the case I am going to revise my cam selection and SEROIUSLY consider a TT2600 converter !!!

If I can spin to 6600rpm I would rather have a bigger cam and a stall and take advantage of the higher rpm....

BTW...rods for the 5.3, 5.7, and 6.0 are 6.098" long with a 3.622" stroke....only the bore is different, the 4.8 is a 6.278" rod with a 3.27" stroke....I would think that the 4.8 would take to higher rpm's easier than the bigger motors because of it's shorter stroke and longer rod

 

If these cranks are the same material, then I don't see why it wouldn't be safe up to 6500-6700. You might want to keep it to 6500 for the 6.0 though.

Check out the graph on this thread.

https://ls1tech.com/forums/showthrea...5&page=2&pp=15

That graph says different about the same rod in the 5.3 and the bigger engines. I wonder which would be right?

 

http://www.mortec.com/borstrok.htm

that was the site that I got the rod length info from...and as fas as I can tell MorTec has NEVER been wrong before

 

It would seem logical that since the 5.3 and 5.7 share the same stroke, they would probably use the same rod length. This would be a good thing to look up the GM part numbers on the con rod for a 4.8, 5.3, 5.7, and 6.0 and see what numbers match.

 

The 4.8 is the one only one with the different rod. Whoever said that was correct in saying they are the same between the 5.3 and the 6.0.

John, do you have some rods you could lay down and eye ball them to see and verify for sure they are all the same length? Maybe the same p/n stamped on them too?

 

I don't have any rods laying around to compare.

 

Well from what I've seen in the past high revs kill internals not so much power. Obviously the stock crank is stout but I'd be weary of the stock rod bolts. The rods are powered metal right? So they are strong, but GM doesn't use anything like ARP fasteners in their motors do they?