Valve lash with aluminum heads

[Mbowling]

I’m working on my 487 and it’ll have TFS heads.  It’ll have a solid flat tappet and I’m wondering if the called for valve lash should be set the same with aluminum heads vs iron?

[blykins]

On iron block, aluminum heads, lash will grow .006" when hot.

[gt350hr]

  it has to be tighter with aluminum heads . I go .005-.006 tighter "cold" than an iron head. Others will have their opinions. Use of an aluminum block would be tighter yet.

[blykins]

  it has to be tighter with aluminum heads . I go .005-.006 tighter "cold" than an iron head. Others will have their opinions. Use of an aluminum block would be tighter yet.

Yep, about .014" on all-aluminum combo.

[Mbowling]

This is going back 20 years but On my 410” all aluminum sprint car motors I’d usually tighten them up by .010-.012.  Which meant with some cams there was zero lash when cold.

[Barry_R]

I usually see about .008 growth on aluminum head/iron block FE stuff.
On aluminum block/aluminum head I start off at .003 to get .016-.018 hot

[Stangman]

I have been doing 8 on my cold setup with aluminum head/iron block.

[66FAIRLANE]

Pretty consistent results. With iron block, aluminium Ebock heads and aluminium Erson rockers I find .007.

[blykins]

Small fluctuations like that could be the temperature that it's ran at, or even the method that's used to run them.

[My427stang]

Aside from holding a valve open at extremes, or if you are right on the edge of clearance, better too tight than too loose.  -.006 is what I use on iron/alum for initial start, but almost always run lash a little tighter in the end.

[plovett]

My "number" is 0.007" cold to hot.  That is with a factory iron block, Edelbrock heads, and Dove rocker stands.   No doubt the number is going to vary.  I don't know what my ambient temperature or "hot" temperature really was when I came up with that number anyway.   So for my 0.018" hot lash setting I used to set it to .010" cold.   Theoretically that'd be 0.017" hot.   A little tight is better than a little loose.

pl

[Nightmist66]

With iron block, aluminium Ebock heads and aluminium Erson rockers I find .007.

I have the same basic parts. Factory iron block, Ed heads, Erson rockers. I also noticed .007" on mine. Looks like Paulie has the same on his, too.