[Pepi]

Originally Posted by johnta1

Yes it should have the '23' before the plant designator (N is this instance)

Here is the pic blown up some ( I added my interpretation to it):

Very faint but you do see what looks like could be the 23.

[71GP76TA]

Just trying to learn more about my car... I posted the PHS a few posts back....and was wondering.... When a Formula 455 was ordered with the SD engine option.... Were there any options that were mandatory when the SD box was checked? I know things like posi...gauges... Y-99... etc was standard on the Trans Am...but were optional on the Formula.... But were they mandatory with the SD engine option???

[Judge273]

That's a good question. My guess would be no.

But, a RAIV did have mandatory posi, and the buyer paid for it regardless. So maybe?

Also, why no AC on 4 speeds again?

[frank.g]

I'm a little rusty on the mandatory option question, but the SD option was more expensive on the Formula than the Trans Am, and my recollection is it had to do with the transmission. Formulas had 3 speed manual as standard, and the SD was only available with automatic or 4 speed.

The no A/C with 4 speed is a multi-faceted issue. The standard rear end ratio in the SD powered Bird was the 3.42. When A/C was installed, the vehicle could not pass the radiator cooling/overheating tests with the 3.42's. The car was able to pass these tests by switching to 3.08's, but the SD and 3.08 combo could not pass emission tests with the 4 speed transmission. So, Pontiac was not able to offer the 4 speed-A/C combo.

[71GP76TA]

Originally Posted by frank.g

I'm a little rusty on the mandatory option question, but the SD option was more expensive on the Formula than the Trans Am, and my recollection is it had to do with the transmission. Formulas had 3 speed manual as standard, and the SD was only available with automatic or 4 speed.

The no A/C with 4 speed is a multi-faceted issue. The standard rear end ratio in the SD powered Bird was the 3.42. When A/C was installed, the vehicle could not pass the radiator cooling/overheating tests with the 3.42's. The car was able to pass these tests by switching to 3.08's, but the SD and 3.08 combo could not pass emission tests with the 4 speed transmission. So, Pontiac was not able to offer the 4 speed-A/C combo.

Interesting on the transmission issue. I never thought about the 3 speed being standard on a Formula. I wonder if any D-port 455 Formulas were ordered with the 3 speed manual?.

[1971WARBIRD]

have seen formula SD's without gauges, doesn't mean they were right, but what I have seen.

[Brewster]

Originally Posted by 71GP76TA

Just trying to learn more about my car... I posted the PHS a few posts back....and was wondering.... When a Formula 455 was ordered with the SD engine option.... Were there any options that were mandatory when the SD box was checked? I know things like posi...gauges... Y-99... etc was standard on the Trans Am...but were optional on the Formula.... But were they mandatory with the SD engine option???

The answer is Yes, I think there where like five items and some where 4 core radiator, HD Battery, safe-t-track, and a few others but dont remember at the present time. Need coffee MMMmmmmm Coffee

[njsteve]

On the Formula you had to order just about everything otherwise you got a stripped car. The T/A came with just about every performance related component, standard (gauges, spoilers, handing package, Formula Steering wheel, 15" wheels...) Here is the two page window sticker from my car:

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[71GP76TA]

I read somewhere that the SD engine option was special order only.... I assume some were ordered for dealer stock too??? Is there any way to tell on the PHS if a car was special ordered? I'm technically the 2nd titled owner on my car... I bought it from a guy that bought it from the 1st owners wife. The guy I bought it from only had it for 2 weeks.

[frank.g]

Originally Posted by frank.g

I'm a little rusty on the mandatory option question, but the SD option was more expensive on the Formula than the Trans Am, and my recollection is it had to do with the transmission. Formulas had 3 speed manual as standard, and the SD was only available with automatic or 4 speed.

The no A/C with 4 speed is a multi-faceted issue. The standard rear end ratio in the SD powered Bird was the 3.42. When A/C was installed, the vehicle could not pass the radiator cooling/overheating tests with the 3.42's. The car was able to pass these tests by switching to 3.08's, but the SD and 3.08 combo could not pass emission tests with the 4 speed transmission. So, Pontiac was not able to offer the 4 speed-A/C combo.

OK - I retrieved my SD thinking cap, and I believe I have the correct information now. First, the SD engine option was for the SD engine only. The reason the SD engine was more expensive on the Formula is the base engine was a 350 on a Formula, while the base engine on the TA was the D-port 455. So, a greater step up on the Formula commanded a higher option price. As NJ Steve stated, everything else would be added at an additional cost. The SD engine was only available with THM or 4speed. This made an upgrade to the transmission, at additional cost, mandatory.. NJ Steve's window sticker bears this out. As far as I know, transmission was the only mandatory required option. Safe-t-track was at the buyers discretion. There were several Formula SD's built with open rear ends. And believe me, they could spin one rear tire all day long. Gauges, too, were at the buyers discretion. Many SD Formula's were built with the standard Formula dash. Several of the Formula SD's were ordered for racing duty, and were ordered with no weight adding options. Without an optional wheel selected, they arrived with dog dish hubcaps.

[frank.g]

Originally Posted by 71GP76TA

I read somewhere that the SD engine option was special order only.... I assume some were ordered for dealer stock too??? Is there any way to tell on the PHS if a car was special ordered? I'm technically the 2nd titled owner on my car... I bought it from a guy that bought it from the 1st owners wife. The guy I bought it from only had it for 2 weeks.

The SD engine was certainly a limited supply option, but it was not a special order option. The SD is listed on a standard sales order form from 1973-4. Once Pontiac made it available, buyers could get them, but often perseverance was required. There was a lot of misinformation/lack of information about the engine at the time. Also, there was spotty availability of the engine, since it was hand built on a side line. At times, customers who ordered the SD had their car built with the D-port engine. Some customers took this car anyway, others refused delivery and reordered. Customers who were determined got their SD. Some SD's did wind up on dealer lots when customers who were tired of waiting, cancelled their orders and the dealer took delivery anyhow.

[74 SD455 Formula]

I know a SD-455 Formula ordered without A/C got the Safety-track 342 Posi rear end as a standard item.

[Judge273]

Originally Posted by 74 SD455 Formula

I know a SD-455 Formula ordered without A/C got the Safety-track 342 Posi rear end as a standard item.

Only way to know is by GM memo?

[OVERULD]

Sorry if this has already been asked and answered, but looking at Steve's window sticker -so, if you ordered a car without the "Functional Ram Air Delete" option, did you then get an SD formula with the traditional formula hood scoops and functional ram air?

BJ

[johnta1]

No, the TA hood was required with the SD engine.

[formula kid]

The engine that was standard depended on the year that it was ordered. In 73-74 the standard engine in the Formula was the 350 2bbl with duel exhaust. The standard engine in the Trans Am for 73 was the 455 4bbl. In 74 the Trans Am engine was changed to the 400 4bbl. If you ordered the SD engine you could not have the Formula hood you were forced to get the Trans Am Shaker. All other options were as the base Formula. Posi-rear had to be ordered the rear spoiler hade to be ordered, the Formula Wheel was a line item order. Formulas came with 3 spd manual transmissions and could be ordered with a 4 spd or automatic which ever you ordered depended on engine, transmission combo and priced accordingly. In the Formula your engine's standard 350 2bbl. Optional engines were in order all with duel exhast 400 2bbl,400 4bbl, 455 4bbl, or the SD-455. Ram air was an option with the 400 4bbl or the 455 4bbl only. I was 17 in 74 and placed an order for a SD-Formula and still remember what you had to do to get one.

[frank.g]

Originally Posted by OVERULD

Sorry if this has already been asked and answered, but looking at Steve's window sticker -so, if you ordered a car without the "Functional Ram Air Delete" option, did you then get an SD formula with the traditional formula hood scoops and functional ram air?

BJ

The functional ram air delete credit relates to the TA shaker hood. The hood scoop had an opening door in 1970 thru 1972, and was suppose to have one in 1973, too. Pontiac set their pricing for the 1973's based on a functioning scoop. Just prior to the 73's availability, EPA set the noise standards for the 73 model year, and the TA scoop could not pass the full throttle test when the door opened. Pontiac's solution was to remove the solenoids, rivet the door shut, and applied a credit for the deleted feature.

[frank.g]

Originally Posted by 74 SD455 Formula

I know a SD-455 Formula ordered without A/C got the Safety-track 342 Posi rear end as a standard item.

All SD's got 3.42's, unless you ordered A/C, then it got 3.08's, plus forced THM. There was no ability for customer to select a ratio. Strictly determined by whether you wanted A/C or not.

[Judge273]

Good informative posts Frank! Learning SD is always fun.

[Alvin]

Originally Posted by frank.g

The functional ram air delete credit relates to the TA shaker hood. The hood scoop had an opening door in 1970 thru 1972, and was suppose to have one in 1973, too. Pontiac set their pricing for the 1973's based on a functioning scoop. Just prior to the 73's availability, EPA set the noise standards for the 73 model year, and the TA scoop could not pass the full throttle test when the door opened. Pontiac's solution was to remove the solenoids, rivet the door shut, and applied a credit for the deleted feature.

And IIRC - Aren't there also 2 or more '73 SD455 emission systems like the other Pontiac engines?

Emission Impossible - Exploring the Differences Between Pontiac's First- and Second-Type 1973 Emissions Control Systems By Rocky Rotella, Photography By Rocky Rotella

The First '73 System

The emission control system used from the start of production in the '73 model year was fairly complex, and Pontiac engineers knew that part-throttle performance would ultimately suffer from it. To prevent any major loss, the system was designed to meet the exact letter of the law. By loosely interpreting the compliance requirements, it appeared as if the engine must be compliant only for the duration of the testing period. So engineers used a time-delay solenoid that allowed the system to operate long enough to pass emissions testing but provide maximum throttle response and efficiency thereafter.
In an attempt to reduce oxides of nitrogen, Pontiac installed avacuum-actuated EGR valve t
Conditions in which the systems operated were limited to a specific range. When coolant temperature was below 71 degrees, TCS allowed full vacuum advance to assist cold engine operation, and EGR was inactive. Normal operation began once coolant temperature reached 125 degrees. TCS then deniedvacuum advance any time the transmission was in first gear or for up to 55 seconds after an upshift from First. Under the same condition, the EGR system operated exactly opposite where EGR was present any time the engine was in First gear or for up to 55 seconds after an upshift.

Together, TCS and EGR controlled the amount of hydrocarbons and NOx emitted during testing or for a short period under normal acceleration. Once the time delay solenoid timed out, however, TCS allowed for full vacuum advance for maximum throttle response, while a second switch connected to TCS denied vacuum to the EGR valve for maximum combustion efficiency. The entire system would reset whenever the transmission dropped back into First gear and the timed process began again.

In the technical sense, the emissions system was compliant. But it did not take long for the EPA to discover that the system was not fully so. Pontiac was given a limited amount of time to find a solution and recertifyevery engine within each respective group or engine production would come to a halt. Caught trying to provide the best running car yet comply with loosely interpreted testing requirements, Pontiac engineers worked diligently to produce a fully compliant alternative to the time-delay system.

The Second '73 System

In response to federal demand, a revised emissions control system was incorporated into engine production on March 15, 1973. The new system contained some drastic changes, many of which are detailed in Pontiac Technical Service Bulletin 73-T-21. The bulletin reveals that the changeover occurred at Motor Unit Number 532727. To distinguish engines with the new system from old, they were painted a darker shade of blue and received a new series of engine codes. It goes on to say that approximately 700 engines before said breakpoint were also converted to the new system and repainted the darker hue. Not only would most transmissions reflect the changes, but rear axles on certain applications would also.

Though performing the same basic function, the operational characteristics of the second-type emissions system were different than the first. It no longer allowed for TCS and EGR operation at opposite times--they now operated independently. A thermostatic vacuum switch in the intake manifold replaced the electric switch and allowed EGR any time coolant temperature was above 95 degrees. TCS, however, allowed for vacuum advance only when coolant temperature was above 125 degrees and the transmission was in high gear. Vacuum advance was limited to just 20 seconds at cold startup to assist idle.