I need a little help on this subject.

I purchased my 1968 firebird convertible in 1968. The car was tagged on the hood as a 350 ... and I subsequently verified that it was manufactured as a 350. I was informed at the time of purchase that the current motor was a pontiac 400. From the engine serial number I determined that it was a 1969 GTO 400. Until recently I assumed that the motor had been replaced at some point. However a few months ago I stumbled upon some information indicating that there was an option available to have a 400CI motor installed in a "non-firebird 400" vehicle. Does anyone have any knowledge of this? I'm reluctantly considering selling my FB and am curious if it's possible that my car may have been one of the 350s upgraded to a GTO 400 motor. Any thoughts?

I apologize. I purchased the vehicle in 1986.

One way to find out would be to order the paperwork from PHS( pontiac historical services). Just off-hand I would say no it's not possible. The original purchaser could very well have had the dealership he bought the car from swap the motor out but nobody in their right mind would do that. It would cost more doing it that way than if they had just ordered the 400 model in the first place. I would say someone is yanking your chain.

You might want to reveal the source of this "information. As Firebob noted, if it is just heresay and not based on some previously unknown technical bulletin, etc. then someone is pulling your chain.

There were dealers, Royal and Myrtle Motor most notably, that would perform retrofits of 428s in Firebirds as well as highly tune 400 engines. It is generally believed these cars started out as base 400 models as this would get you better engine cooling, springs, and other components.

I'm trying to track down the link indicating the possibility of gto 400s installed in firebird 350s. I thought that I had emailed myself the link ... but apparently I did not. I may have saved it as a favorite on one of my work computers. I will re-post with the link and vin and engine serial numbers at a later date. Thanks to those who have offered opinions and advice.
dogbone

I’ve owned mine since April ’85, but I can only document ownership to 11/5/86. It’s possible that the dealer installed it as new-car make-ready work, but phs won’t show it because it’s the factory invoice, not the dealer invoice.

I used to be a GM technician, but everyone around here used to be a GM technician; ask them! One of my older coworkers used to be a Pontiac technician at David Mc David Pontiac, Irving, TX, when these cars were new.

Here is a paraphrased statement from new-car Pontiac service tech, with me paraphrasing as accurately as I can remember in ’87, as I was prepping my car for paint. The thing is that I don’t see why he would be lying, because he was a professional technician reminiscing about his career, not some hobby car guy running his mouth.

His claim was that new Firebird sales were dismal at best, and while the new models were released, the parking lot was full of the previous years. One way to unload old stock was to install a 400 in the car without charging the customer. According the technician, this was a collaborative effort between the factory and dealer. The dealer pulled the 350, returned it to the factory, and they used them as ‘service replacement’ engines. If it were a slush-box car, I don’t know how they dealt with the th350/th400. My bad, and I should have asked him. He’s most likely dead by now because he was in early to mid 60s in ‘87.

Again, it defies logic why he would fabricate such a story, and it fits into the history of these cars because people didn’t want them, reflected by comparing today’s value with the Camaro. PHS would not show this change because PHS is factory, not dealer, invoice; also, it wouldn’t be a ‘special order’ because they were simply finding a way to unload obsolete stock.

I’m always more than receptive to entertain oddities that don’t conform to the norm. So try to find that link because I would love to see what you found, and it ties in well with what the Pontiac tech said.

Oh yeah! Are you sure that you’re ready to sell it? I couldn’t imagine selling mine.

Of course I don't know for sure one way or the other but my question would be why would they use GTO coded engines as replacements? Why not Firebird coded? Or even SR engines that weren't coded at all? They weren't, I suspect, having trouble selling GTOs at the time. And GTO motors and Firebird motors were exactly the same except for the carb. So why would they specify GTO motors? It sounds kind of unbelievable to me.

Maybe "upgraded with a 'real' GTO 400ci engine at no extra cost" was a good enough inducement to move the cars off the lot?

This is what's known as a "sea story".

Someone dropped a 1969 GTO engine in your 1968 Firebird at some point over the past 45 years. That's the most logical explanation.

Pontiac sold 107,112 Firebirds in 1968. There was no shortage of these cars, and no issues with them "moving them off their lots".

If it was a warranty claim, it would be an SR coded block.

The ONLY story I can think of where dealers changed engines to "get them off their lot" was with the 1969 ZL1 Camaro, where a dealer was stuck with a few of these cars due to their $8,000 price tag (double the price of a 1969 Camaro). They yanked the ZL1 427 out and dropped in a 350 or 396 to get rid of them. The dealer then sold the ZL1 engine separately.

On a different tangent, some Plymouth dealers, left with unwanted 1970 Superbirds by 1971, and high-perf cars being harder and harder to sell, yanked off the nosecones and wings and sold them as regular Road Runners.

If the dealer was to upgrade with a GTO engine, would they have used a 400 block with a VIN number on it? I wouldn't think so. Even if so it would still be documented as a 350 as others have stated. Rally a mute point with out documentation from the dealer.

Having been a dealer (no, not a mechanic/technician) , and yes , not GM dealer, but still, I really doubt a dealer would install a GTO engine in a Firebird ,brand new under warranty as you would get 'issues' when/if you had warranty claims.

Besides, there's no "upgrade" to a GTO engine. It's the same engine as in a Firebird 400, except the Firebird uses different exhaust manifolds. And the fact it's the wrong year engine further adds to the fact that it's just a transplanted engine.

I was under the impression that the difference was the carb on the Firebird was restricted/de-tuned a bit in comparison to the GTO carb.

David

In 1967 and 1968, Firebird 400's had a limited secondary opening, easily fixed with a pair of pliers. When corrected, Firebird 400's always outran GTO's in side-by-side tests, due to their lighter weight and better flowing exhaust manifolds.

There was no "upgrade" to a GTO engine, the Firebird 400 and GTO used the same components, just different part numbers for the assembly process.

Back to the original question....you have a transplanted 1969 GTO engine in your 1968 Bird. Nothing to be embarrassed about at all, unless of course you paid for a matching numbers Firebird 400.

Bjorn: You said that you owned a dealership. Please tell me what type of cars you sold at your new-car dealership; also, explain to me how such a transplant would affect your vehicles’ warranty.

So I have a little more information. The other serial numbers on the heads, manifolds etc have 1969 serial numbers. Anyone want to take a crack on Id'ing this motor?

passenger side front of block

0842409
2889
YS



passenger side back of block behind distributor

9799914

70 gto 400. 350hp
This is what I found here. http://www.pontiacpower.net/engcode01.html

YS A-body 70 400 350 Turbo 400 L-67 1x4 9799914 2 GTO

Thanks for your input HaroldB.

The thing I'm curious about is:

0842409
2889 This number? I know it's not the standard pontiac method for date code. What is this number?
Could it be a date code? 28th day of 8th month 1969?
YS

ys engines were also used in the firebird formula in 1970

2889 is probably the work order code for a rebuilder

it was stamped into the block when it was rebuilt by a machine shop

That is the number right above the YS? If so, that is the Engine Unit Number, It matches the Engine Unit number on the build sheet.