You can rebuild your Ford F150 engine but only using engine parts built for
your Ford truck. No modifications can be made to it. You don't have to use
original Ford engine parts, but whatever parts you do use have to be built
for your Ford and have an EO (executive order) number on them. The EO number
shows the smog station or smog technician that the parts you used are
designed for your Ford. Bigger pistons are definitely out of the question.
Though it would be difficult for a smog station to find out you've rebored
your Ford's engine, more then likely, emissions will increase and you'll
fail the smog test there.
Plus, and most truck owners don't necessary follow this law, but once any
engine is rebuilt a smog check referees office needs to conduct the smog
test only. Once the truck passes the smog referee's test it is issued a blue
tag indicating the engine job was done properly and it does not pollute.
