FormulaBoat

iTrader: (1)

I just picked up a set of slightly used heads that were formerly on an Ilmor marine engine, they have a beautiful orange paint job. I'm slightly confused, but hopefully just from my own lack of experience. The heads have the following features, of which I think a few or most of these typically identify them as LSA heads, but that does not align with the common conception of the 821 casting number on them:

LSA "wing" bump in the intake port, short inside radius side wall of the port as it turns
LSA supercharger locating dowel receiving bore on intake sealing surface face
Seemingly hollow intake valves (mass 80-83g, forgot exact)
Additional little casting nugget bump in combustion chamber between intake valve and combustion chamber edge (this common on any?)
Infamous "blue" valve springs
1 of each of the steam ports on each head factory plugged off, I think most later heads have this regardless....

Were 821's used on LSA's? Were intake port wings used on non-LSA engines? Locating dowel hole? Any of this making sense to anybody? Most indicators I researched just produced a conflicted result.
Thanks as always.

G Atsma

LSA used 4863 rotocast heads. They ARE different from LS3 heads

FormulaBoat

iTrader: (1)

Same as I found in info. What do you think I have? A set of creepers?

G Atsma

Any way that little port "wing" could be shaped in there via some creative porting?
As far as the little bump between valve and chamber edge, a picture would be helpful there.
The rest concerns hardware that anyone could attach.

FormulaBoat

iTrader: (1)

G Atsma

I would have to see another 821 head to see if the little bump is there. I bet it is, as it appears cast in.

FormulaBoat

iTrader: (1)

It is cast in.

Anybody with 821 or LSA head experience? Is the intake ski ramp on 821 heads?