Alexandre, I checked my Hayne's shop manual, and the 2.5 used in the eighties GM front drives used 10 head bolts. According to a 1974 Chilton manual, the old 153 used 10 head bolts. Hope this helps.
Tony, I always thought the "Iron Duke" moniker was used by Pontiac when they reintroduced the 2.5 l., so as to distinguish it from the extremely lame Vega/Starfire engine. I don't remember the old 153 being called anything but "slow" - Chevy II's with this engine were in danger of being run down by kids on bicycles!
[ 12-20-2001: Message edited by: Locobreath ]
[ 12-20-2001: Message edited by: Locobreath ]
[ 12-20-2001: Message edited by: Locobreath ]
