Originally Posted by GonneVille
Originally Posted by SSsuperchargedEi
zl1 is an all aluminum 427 that was only an option from 67-69... known to push in the neighborhood of 530-560 at the crank, but modesly rated at something like 425
Actually I believe the ZL1 was the iron-block/aluminum head 427.
The all-aluminum 427 was the L88. Both of them turned out in excess of 500hp, but shared a GM rating of 425, 10hp below the Tri-power 427. GM pulled this bit of skullduggery to keep their most powerful engines to their factory racing teams.
Keep in mind that those numbers are the GM-inflated gross
-hp rating. In truth, the L88 only turned out around 420 net hp. The Tripower didn't even mange to crack 350 net-hp.
thought the L88 had an iron block....
69 was the rarest year for the zL1, only something like two exist