Is this correct?
Forged pistons if fit properly don't rattle much when cold. My HP273 with
100,000 miles and factory forged pistons doesn't rattle when cold. If they do rattle excessively when cold the piston to cylinder wall clearance is too loose.
Cast pistons work great for most street engines and with the HP-273 there isn't much available for forged pistons. Egge has cast pistons listed and Flatlander Racing lists forged pistons in any bore size and compression ratio although I have never contacted either place to confirm that info. The factory 273 pistons were forged with the 2 barrell motors having flat tops with 4 valve reliefs and the HP motors had a slightly domed piston to raise the compression. toolmanmike