The heads are aluminum, the block is iron.
Iron and Aluminum
Most cylinder heads are made from cast iron or aluminum.
Some have aluminum engine blocks and/or cylinder heads, many of the sensors, intake manifolds
yes
Aluminum.
YesYes
There are several oil return holes in the cylinder heads.
The cylinder walls will be cast iron. The heads are either cast iron or aluminum.
yes, iron block w/ aluminum heads.... ls1 has aluminum block and aluminum heads
Yes but I think only 1 head if a 4 cyl
They're under the upper intake manifold next to the cylinder heads.