A big block Chevy head with oddly angled valves first used in '63 in stock car racing at Daytona and later used as a high performance option on 396 powered '66 Chevys starting in '65 with the rollout of the '66 model year cars.

The porcupine was first available in the 65 corvette as a 396/425hp square port solid liter version, the 65 z-16 chevelle as a 396/375hp square port hydraulic lifter version, and in the big car, impala belair biscayne and caprice as a 395/325 or a 396/425 sleeper.

First seen in Mark II 427cu in mystery motor run at Daytona in 1963. First offered for sale in 1965 Full size 325 and 375/425 hp, (ain't never seen a real one identifed as a 425 hp though) Chevelle 375 hp and Vette 425 hp all 396 cu in and last offered in 2004? trucks like my motor home in 8.1 liters 498 cu in. and the world has never been the same.

Offered with oval port, and retangular port heads during the muscle car era in 396 402 427 454 cu in. and in select cars in 1969 and 1970 with aluminum heads.

And I know other stuff too.

1 Chrysler response 2 Chevy responses = 3 answers, all wrong! Try again.

How could I be wrong? You asked what I thought I knew and I told you.

Your probably going to talk about some weird obscue MOPAR thing that knowbody cares about.

Couldn't the term "porcupine" head refer to any splayed valve head? Also, I think Chevy tried to make a porcupine 302 small block head to try to keep up with the Ford Boss 302 for Trans-Am. These were prototype only (I think).

That was a tough one. I had to eat a huge dish of rigatoni and think on it.

ls5 360/ls6 450 hp chevelle,monte carlo, el camino.
ls5 and ls6 corvette
ls7 corvette an updated version of the l88 never really happened.

bill

One could argue that the first use of the term porcupine head goes back to early motorcycles well before any automobile engine use of the term.

The first commonly recognized use of the term Porcupine head was on the Mark II 427 NASCAR motor. Chevy started development of that design in the late 50's and that was long before Chevy 302 small blocks and Boss Fords. Nuf said.