what are the difference between the 2.8 and the 2.9 V6?
Is it true that they are the same block?

 

yes they are the same block but for some reason you can use the 2.9 heads
on the 2.8 but not 2.8 on 2.9 due to the fuel injection i think the intake ports are different

 

The biggest difference between the 2.8 and the 2.9 is the 2.8 is carburated and the 2.9 is fuel injected.

 

Not even close guys, the 2.8 is a close relative, not a twin,
to the 2.9. For one thing, the 2.8 has a gear driven cam,
where the 2.9 uses a timing chain, the 2.8 heads have a
different intake/exhaust pattern, and the cams are different
because of this... So the only major items that will swap
between the two are the crank and the bell housing...

SteveL

 

WHAT YOU SAY ON THE HEADS!!!!!!! what ever