According to the build sheet, my GTO originally had a 400 HO engine. Somewhere in it's life someone swaped it out for a 455.

Here is the engine as I got it:

Since then it has been rebuilt by Mike Zimmerman at Zimmerman racing:

Just a few detsails:

* Edelbrock Performer heads

* Edelbrock Performer intake

* Edelbrock 800cfm carb

*Dyno'ed at 535hp, 612 ft-lb torque