[poncho-mike]

I just have one additional point to make.

I'm a design engineer, so I know a lot about how manufacturing works.

The production floor and the warehouse does not like to keep two different part numbers for the same application. If a part goes through minor changes and can replace an existing part, the existing part is superceded and is replaced by the new part. In many cases, the tool for the existing part is modified to make the new part number, so it's not possible to make the old part any further.

If I were an engineer designing the SD455 and I wanted to install an aluminum intake, I would not use a part that has been obsoleted. Lloyd has shown documentation that indicates the 485460 intake was out of production well before the production parts were being tooled.

Somebody in engineering probably did some testing on the SD455 with a 485460 intake, but it was probably one laying around in engineering for a few years. The guys in engineering have access to all of the goodies.

Mike

[formula kid]

If you go to the listing for 67-81 firebird and TA parts for sale you will see that there is a thread for 73 SD Aluminum intake for sale. When I first saw the post on E-bay with a $18000. buy it now I remembered that there was another intake #485640 that sold in June of this year. The listed manifold is at $500.00 and the auction will close aprox 10:38 PM today. A few of menbers have pulled out our books and have look at our manifold to see if we could help shed some light on the question of if this manifold was ment to be used on the SD455 engine. I have see some pictures of the 485640 manifold but not able to see the exhaust crossover the was to go with it. Remember the choke stove for the SD is not the same bimetal hook up as the as the 69-70 Ram Air or the 71-72 Ho455. It is a tube that goes down under the maifold and one tube is connected to the rear of the carb, and the other to the choke housing. This would mean the the carb choke house was also changed for the cast iron maaifold. This has been viewed over 1057 times and is one hot topic. I hope we can figure it all out one day.

[The Boss]

Not to beat a dead horse, but my 72 (December build date) has the 485640 intake as well.

[brians]

Rocky:
If your keeping track of dates.
I have a #488945 with a 12-15-71 date

Pulled the whole engine from a 72 T/a in 1986.

Brian

[Rocky Rotella]

Hello Jim, it’s definitely been a while!

I had the chance to speak with Pete McCarthy this week and asked him where he located the information on that manifold. He said that when material for the book was being gathered nearly 20 years ago, that was the information he had at that time. As he recalled he had only seen the 485640 available in the parts manual, never on a car. And because it shared the same 485- prefix with many other SD parts, he made the deduction that it was a non-production SD intake. However, we have uncovered much over the past 20 years, including 485640 on so many cars. So that may clear up much of the mystery why Pete’s book says what it does!

Now, we need to determine exactly what is different between the 485640 and the 488945. If there was no difference, it is unlikely that a part number change was necessary. Does anyone have one off a motor that they can take detailed pictures of?

[turbo]

Hi Rocky, you may want to email a member of the group Northern Goat. He posted on this thread. I sold him my intake. I as sure he would help you out with some pictures. I remember sending you some pictures of my intake awhile ago. I don't know if you still have them. It looks very similar to a 72 HO number 488945. I am glad you spoke to Mr. McCarthy to try to unravel this mystery. Someone must know why pontiac changed production numbers for this intake. It has peaked many of our interest. Good luck finding the answers. If I run across anything I will gladly share the information. Thanks Jim.

[Rocky Rotella]

Jim, I do believe I saved those pictures in my files…somewhere! I had the chance to view two 1972 cars at the POCI Nats in SC this weekend; a ’72 Trans Am with a 488945 and a one-owner, Sept 71 built, ’72 GTO (a BLACK post car, BTW) with a 485640. Looking at both up close revealed no visible exterior differences.

Basically, what I am now looking for is a detailed shot of the bottom of a 485640 to verify the location of the bossed the crossover attached to.

It may take a LONG time but eventually we’ll figure this out.

[turbo]

Rocky, I just sent you a picture of the underside of the intake. I kept a few pictures. Hope the picture came out o.k. Let me know. Jim

[Jim Robertson]

In an effort to find out about the 488945 manifold I did some digging and found this thread...so I am resurrecting it.
From reading this thread and others, the consenus is that "early" cars had the 640 manifold and the "others" had the 945 manifold. Does anyone know the date of the part number switch?
My 945 manifold is clearly dated Oct 25 1971.

Next question should spark some discussion...
How soon after the casting date on an intake manifold would this part actually be installed on an engine? Then approximately how many days/weeks later would that engine be installed in a chassis?

Trying to piece this 1972 puzzle back together that someone so inconsiderately scattered,
Jim

[1971WARBIRD]

have a 72 HO 455 that was bought separate from car.
heads 7F6 cast A052 no scallopes on intakes
intake 488495 cast 12-20-71
next time in garage i'll see what the dates on the carb and block are.

[giles]

I can't speak directly to 72 production timing, but keep in mind that HOs were very low volume in terms of total Pontiac engine plant output. 3000 a year or so out of several hundred thousand V8s. The castings would be made in lots, maybe a couple hundred at a time, and then the individual engines might be made sporadically mixed in with regular procdcution.
My 04A assembled 71 TA has its original engine with a 7/1/70 production date for the intake. I assume they cast most of the intakes for the model run in one shot.
As far as timing of your engine, the castings could date to several months before the engine was assembled (the unique intake and heads anyway), but the engine was probably built somewhere between 3-6 weeks before final assembly. The engine build date was not recorded anywhere that I am aware of (just casting dates). The only real "record" of assembly is the Motor Unit Number stamped on the front of the block next to the two letter alpha code. This number is a serial number assigned by the Pontiac engine plant and would indicate where your engine falls into Pontiac V8 production for the year.

P.S. This is the first that I have seen of this old post, but would concur 100% with Rocky that no 73 cars were made with aluminum intakes. New emissions regs for 73 basically mandated EGR and as we know there never was an aluminum intake that incorporated EGR.

['ol Pinion head]

Giles, not sure the deal on your '71's HO intake, but there were at least 5 different production dates on the production '71 intakes. I have 3 different date HO original '71 intakes & have had a few others.

From what I've observed on the SD stuff, definitely very few dates.

[Lloyd-TX]

Additional SD casting date info, FWIW . . .

Casting dates on my recently sold my '74 Y8 (M40) SD block and intake, and the heads I still have:

Block: C294
Intake: E134
Heads: F163 and F233

Those I trust can PM or e-mail me for block VIN and EUN if you like.

[superdutybob]

Lloyd:

Please put together a list of those you trust so we know whether to email you for the info or not.LOL

[Lloyd-TX]

Originally Posted by superdutybob

Lloyd:

Please put together a list of those you trust so we know whether to email you for the info or not.LOL

Well . . .

I've been guilty - on countless occasions - of posting sensitive info that the unscrupulous re-stampers and the like can and will use to fake a block, or a car for that matter.

Those who know better have reminded me that we've ALL got to be careful about what we post in "public" places.

Block EUN's and VIN's, carb plant (pick) codes, even some casting dates are valuable info to the thieves out there.

BTW Bob - if I had a list of those I trust with this kind of info, you'd be on it. If you'd like the VIN or EUN from the block, ask away.

[rwinkles]

For what it's worth, I have a 640 intake with a casting date of 8/11/71 - an early '72 production part. I do remember buying a new 640 back in about 1975 or 76 from the local dealership with a friend when he was replacing the intake for his '69 Ram Air IV GTO. He ordered the replacement part and got the 640.