Yes they are the same.
The heads will fit the block, but the vortec intake manifold will not bolt to the old style heads.
no such thing as a vortec 5.3 tbi
No it will not, Totaley different.
will a 4.3l vortec starter fit a 305 vortec?
yes they will fit, but you will need an intake manifold compatible with vortec heads if you plan on reusing the carburetor
yes
No. There were major engine changes between those years.
On a non-TBI engine, Yes.
yes, just need to change the fuel cross over line cause it wont fit
All of them. Some were carburated, some fuel injected. Just pick the right one.
Yes it will. It will bolt right on... 100% interchangeable.