[frank.g]

All SD's built for production (the ones with an "X" in their VIN) were after the emission change over date, so all have the later emission system. Some intake manifolds were originally manufactured for the earlier system, and they were re-tapped and stamped with the later part number. Occasionally, you can see the double stamp on some of these manifolds.

[Alvin]

Originally Posted by frank.g

All SD's built for production (the ones with an "X" in their VIN) were after the emission change over date, so all have the later emission system. Some intake manifolds were originally manufactured for the earlier system, and they were re-tapped and stamped with the later part number. Occasionally, you can see the double stamp on some of these manifolds.

Cool thx. Reason for my Q here:

The next time you see a '73 Pontiac model like Steve Schappaugh's SD-455 Trans Am, check under the hood and take a close look at the emissions control system. Many fail to realize that two separate systems were used that year. Although each had the same basic components and functioned similarly, the early system fell victim to the EPA's watchful eye. Continue on as we discuss the first and second types and explore why changes occurred. Read more: http://www.highperformancepontiac.co...ntrol_systems/

[frank.g]

Interesting observation. Steve Schappaugh has had many SD's over the years, and it has been a long while since I have seen any of his, so I don't know to which car the observation is referring to. It's an open ended statement, so I can't tell from it whether Steve has a pre-production car, whether he retro fitted an early system to his car (unlikely as that would be) or whether he got the one that slipped out the door. I have learned thru the years with GM to never say "never". But, I will say, for all my years that I edited the SD Registry, none of the cars registered were built prior to the cutoff date that the emission system switch occurred.

[johnta1]

That blurb from the text under the picture was referring to the fact that the SD was different than the early engines I think?

Here is what was in the article later on:

Discussing the emissions system of the Super Duty 455, McCully stated that preproduction SD engines with the 041-spec camshaft such as those found in the engineering test mules and press cars should have had the first-type system. But EPA certification for a cam change delayed the SD's release until late April 1973. Since the changeover to the second-type system occurred prior to that, it is unlikely that any production SD engines received the first-type system.

The thread on Micheal's 'test' TA probably had the 1st version egr.

[71GP76TA]

After a little research... I found this.

*N41 Power steering and JL2 Power disc brakes were required options with the SD-455

[74 SD455 Formula]

Here's a copy of my build sheet. Hope it's big enough to see.

[TimsTA]

http://www.carsinbarns.com/new259.htmlHope someone can save this one someday!

[71GP76TA]

Originally Posted by TimsTA

http://www.carsinbarns.com/new259.htmlHope someone can save this one someday!

Beat me to it..

[keith k]

Originally Posted by 71GP76TA

Beat me to it..

Not that the factory was super precise in the placement of the shaker engine call out decals, but that SD 455 decal looks abnormally high. Wonder what the VIN says...

[SD73]

Originally Posted by keith k

Not that the factory was super precise in the placement of the shaker engine call out decals, but that SD 455 decal looks abnormally high. Wonder what the VIN says...

Actually that looks pretty accurate. Most people restore them on the low side.

[Norwood]

Is that picture dated?

[TimsTA]

Not sure if picture is dated, but the website usually has weekly updates. Would be nice to know the story behind it! Wonder if those are the original Uniroyals on it. Interior looks pretty good. Maybe it had Engine problems and was parked.

[Brewster]

Cool picture of a bird delete custom interior duty and odds are it sports a/c and an automatic?

[Norwood]

I'm just wondering if that picture is twenty years old.

[keith k]

Originally Posted by SD73

Actually that looks pretty accurate. Most people restore them on the low side.

Probably a good thing I seem to favor '70s then... I won't have to worry about intentionally mis-positioning the shaker decals

[71GP76TA]

Originally Posted by TimsTA

Not sure if picture is dated, but the website usually has weekly updates. Would be nice to know the story behind it! Wonder if those are the original Uniroyals on it. Interior looks pretty good. Maybe it had Engine problems and was parked.

Judging by the font of the letters... I would say yes.. Probably a very low mile car.

[johnta1]

Quote:
Originally Posted by keith k
Not that the factory was super precise in the placement of the shaker engine call out decals, but that SD 455 decal looks abnormally high. Wonder what the VIN says...

Actually that looks pretty accurate. Most people restore them on the low side.

Decal placement for scoop:

[74 SD455 Formula]

Originally Posted by Brewster

Cool picture of a bird delete custom interior duty and odds are it sports a/c and an automatic?

Brew,
It's a non A/C car with an automatic.

[The Boss]

What's the story on this one - anyone have any history?

http://www.ebay.com/itm/171491328203...;3AMEBIDX%3AIT

[Brewster]

Cool, most of them came with a/c making this car a little more desirable.

John, the lineman used jigs as starters regarding the placement of all decals however once experienced that diminished. Bottom line anything was possible when it came to the locations of these decals as we have seen.