Pontiac 455 hp reduction

[oldskool]

Originally Posted by Billy Nees

Umm, I don't think that he posts on here but Phil Szupka owned an original 73 GP/ 455SD!

Yeah, we've all read about stuff that came off the assembly line that wasn't suppose to. And a variety of VIP's could usually special order something that was not available to the general public.

Here's a quote from an '07 Motor Trend article. Don't know how much research the writer did. And I didn't see every '73 GP that came off the line.

"... no SD-455-powered Grand Prixs were ever factory produced..."

https://www.motortrend.com/news/hppp...ac-grand-prix/

Pic #4 is of an H-O Racing Specialties newsletter with John Clegg's '73 GP on the cover. It says that he ran it @ Indy with SD455 power, although it don't say that it was an original SD455 equipped car. But it does show that NHRA allowed the SD455 to be used in a '73 GP, from the early years. So, maybe that's the info that Pontiac gave NHRA, at the time.

Mick Leiferman ran a '73 GTO. I've read that it had SD455 power. If that's true, don't know if it came with the SD455 or he swapped it in. For the non-Pontiac guys who don't know Mick Leiferman, he ran a '71 GTO that was a 5-year nat record holder & who was Stock RU @ Indy 3 years straight.

Here are pics of his '71 & pics of his '73, with 2 different paint jobs.