Induction hardened 8660 is stronger but more brittle. When it fails, it FAILS. 8620 will have good surface hardness but a tougher core.

Honestly, either is going to be fine. I tend to prefer 8620 for the street.

 

Yea that was Thunderstruck...I believe he put a Cam Motion 205/210 in a 5.3.

 

They are both excellent for most LS applications if they are ground and finished properly. They both will have excellent surface hardness and wear characteristics. What is unique about 8620 is that, due to the hardening process, the 8620 cam core maintains its ductility. This allows it to live in extreme environments where an induction hardened camshaft might fracture.

 

So with the above in mind, is the 8620 worthwhile on a mild street cam, like your truck series, for example?

 

Any of the 3 alloys can do the job in this application. Our Cam Motion 5150 cams should outlast the truck.

 

No way would I cam any engine without doing a minimum of pushrods and at least yellow GM springs. If you cant afford those, dont cam your engine. That being said, I agree with the person that stated long tubes will do wonders. Mine really woke my 6.0 up in the mid to upper end range and really help for towing.

 

so you figure induction is deeper than case? and do cams need flexibility? what for?

 

Ductility is good for general toughness and for fatigue life. Camshafts flex a little just like everything else. Hell the main bearing caps flex a little when torqued.

Truth be told for a street machine, worrying about the camshaft alloy is a bit like majoring in the minor and minoring on the major. If that makes any sense. If you were doing super high lift and spring rates it would be more of a concern.

 

https://ls1tech.com/forums/dynamomet...hp-22rwtq.html

 

Another great thing about the LS platform is the 55mm bearing journal camshaft design. This allows the LS camshafts to have a much thicker barrel than the old small block Chevrolet camshafts. This extra heft makes the LS camshaft much stronger. In this application, the less expensive alloys are still plenty strong for most any common application.

 

Thank you both for answering with good comprehensive and above all HONEST answers! Not trying to upsell, and that is refreshing nowadays!

 

It's not the cam core material that was the problem with Comp anywhere... nor was it the finish.

It was something much more fundamental. I am running a Comp Cam in my car. No problems. Just make sure it's Post-Jan 2016 build date for their new "tech" to make it into the cam.

 

If it wasn't the material or finish, can you say what it was? Or am I not seeing something here? (which is entirely possible! lol)

 

I know it's only one data point, but one I had was nine degrees off. Advanced. At first, I thought it was a tooth off, but moving it a tooth moved it 18 degrees, so it was half a tooth off. So, mine was a grinding error.

 

Well that answers my "do I really need to degree the cam" thought.

 

True, one should degree a cam just to be sure, but 9 degrees is pure sloppiness on Comp's part.

 

Thats one reason why i like cam motion so much. After grinding they put each cam on a cam doctor and verify it before shipping. That has value

 

And that's why Comp's name is headed straight for the gutter around here...

 

Years ago Bullet cams were known to do this. For my SOHC 2 valve Mustang one came 9 degrees retarded and the other 5 degrees retarded

 

Awesome. Noted.

That's really retarded (couldn't help it)