spel chek - Chevelle Tech
Test Drive New to this area?
Test post and edit your own messages.

  • 1 Post By Cam
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 3 (permalink) Old Oct 6th, 19, 2:03 PM Thread Starter
Gold Founding Member
Cameron Milne
Join Date: Sep 1998
Location: Toronto, Ontario, Canada
Posts: 7,748
spel chek

A very interesting & unusual car, I hardly remember seeing any even when they were brand new.

Pontiac was trying to shift buyers upscale into the sophisticated Grand Am, since pure raw performance looked like it was not long for this world. That, plus the GTO name was an assigned risk according to insurance companies. Yet horsepower was down. The switch to net ratings dropped power on paper, but in the mad scramble to meet the increasingly tough emissions standards they had to lean out mixtures, retard timing and dilute the intake charge with exhaust gas (EGR) to reduce combustion temperatures in an effort to reduce oxides of nitrogen & other pollutants. All of this had the effect of lazy throttle response and high fuel consumption. In fact it has been said by engineers that if your 1973 or 74 model can operate across it's complete operating range without some sort of stumble, hesitation, run-on or backfire then it is not tuned to spec. Without things like a catalytic converter to clean up exhaust downstream, they had to fiddle with it until they were able to certify the cars for sale. This also means that they can easily be re-tuned for more power & better economy. Legal, well technically no...

Regarding the SD-455, it wasn't really so much of a certification issue, although they did have time getting certified (they had to make changes that brought power down from 310 to 290 net h.p. & delayed introduction), probably the bigger issue was parts pilferage at the engine plant itself. After casting up all the parts for about 1200 engines they found that they only had enough parts to complete about 600, so the Trans Am (and a few dozen Formula 455s) were the lucky recipients of that high-performance rogue that really shouldn't have existed during the emission-compliance engineering crisis at that time.

I would love to see that '73 brought back but they are not really supported much in the restoration parts business, and the plastic interior bits after so many decades must be about ready to disintegrate. Probably the best way to restore it would be to raid a more pedestrian survivor for sheet metal & interior bits. The colonnade cars just haven't hit the critical mass of support that would encourage restoration parts manufacturers to invest profitably.
Kirk's67SS likes this.

"The more you know,
the more you realize there is that you don't know." - Dad

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

TC Gold #120

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Cam is offline  
Sponsored Links
post #2 of 3 (permalink) Old Oct 9th, 19, 10:39 PM
Senior Tech Team
Join Date: Apr 2011
Location: Ottawa, On, Canada
Posts: 4,992
Re: spel chek

wondering what car and if this should be some where else/another Forum rather than " TEST DRIVE " ?

67 Chevelle Malibu SS Cdn
Born 283 / PG / A51
468/TH400 2,500 stall/ S60 3.70 Gs
Prev Best on M/T ET S/S #3454 street Tires/Dress 2018/05/20
60' = 1.664
1/8 = 7.532 et / 91 mph
1/4 = 11.814 et / 115 mph
NEW Best with 3,500+ Stall TC 2019/09/08
60' = 1.547
1/8 = 7.311 et / 91.76 mph
1/4 = 11.595 et / 114.28 mph

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Kirk's67SS is offline  
post #3 of 3 (permalink) Old Oct 10th, 19, 12:16 PM
Lifetime Premium Member
Join Date: Nov 2012
Location: San Diego
Posts: 1,008
Re: spel chek

Think he's talking about the 73 GTO.


70 El Camino SS 396
68 GTO (Thanks Mom)
06 Silverado
07 SRX
OO52 is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:


Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome