LS6 cam

[Steven J]

I noticed that the valve lash spec for the Crane cam is significantly different than the original GM cam. Anyone know why ?

[Chevy454]

Not sure...they just changed it within the last year on the cam cards, even though everything else is the same...my guess is that the rash of flattened cams within ALL cam manufacturers has them tightening up their clearances...but that's just a guess. I have that cam and it likes the 24/28...

[YENKO DEUCE REGISTRY]

Did the cam mfg's change the type of metal composite in their blanks?

[Chevy454]

I kinda think they did, but have never gotten a straight answer...last I knew the better part of all the cam blanks used in the market came from the same place, and *all* cam mfg's have been having cam failures. Looks like simple math to me!

Jim Lerum was the one who spotted the different lash on the 143 card...he built an LS6 and then had a cam go bad, so had another put in...he was checking out his newest cam card and spotted the 25/25 and told me about it...everything else on our cards was the same, and it even took them a while to change it on the website...but for whatever reason they call for 25/25 now...

[Steven J]

I'm seeing .016/.016

Part Number: 19038 Grind Number: 143 2A
Engine Identification:
Start Yr. End Yr. Make Cyl Description
1967 Up CHEVROLET 8
Engine Size Configuration
396-454 C.I. V

Valve Setting: Intake .016 Exhaust .016 HOT

[Hotrodpaul]

That is probably lift at the LOBE. Multiply .016" X 1.7 Rocker Ratio and you get .027"

Paul

[Chevy454]

Hmm...guess it does say 16/16...for some reason 25/25 was stuck in my head...