F.I Plunum Serial #1 through #50 Do You Have One?

[Monte M.]

I am looking for any of the 1963 fuel injection plenums that have a low serial number on them. I know the typical unit has the 1000 place holder for the average serial number to be 1075, or 1156 and so on. But there were a few plenums sent out really early before they used the 1000 place holder.

If you have one, or know of one, of these early plenums, can you contact me?

I know some of you do not care to share your information with everybody. If this is your case, you can send me a PM, or you can reach me at:

These low number plenums were typically used for testing and a few of them made it out of the factory on cars. I am just trying to get an idea of how many of them are out there.

Thank for taking a look.

If by chance you know of any of the early units used on race cars, they are of interest too. Grand Sport #004, and the gulf oil cars had modified units along with a bunch of other race cars. Any pictures or information on these experimental units are of interest as well.

There is no real reason for the gathering of this information, but I just want to gather as much as I can before it gets lost in time. So, the next generation of Corvette lovers can enjoy it if they have an interest.

[Frank B.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

I will research my information and contacts to see if anyone has a real early unit, and I'll get back to you.

I have a question relative to what serial numbers would be appropriate for a November 1962 built car. This car has roughly unit #175, with a base-plate casting date of 9-6-62, and the exposed bolt cavities under the nozzle blocks. Some say it's too early for the car, but I tend to disagree. Any feedback will be greatly appreciated. Thanks

[Monte M.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

Frank,
First, I want to say that I also have a November built fuel injected 1963 Corvette. My coupe is in the #33XX range.
Second, just so we are clear, your serial number on your plenum is #1175, not #175 I hope. If it is #175, we have a whole nother conversation to have.
Next, as far as the numbers being correct, the baseplate works fine, but the plenum is another matter. According to the units that are registered, the number should be in the 3400 and the 3600 range. A Lot of people are going to say that 1300 to 1600 will work best, but it is just a matter of opinion. But, that is in a perfect world and we all know there was a lot of things mixed up back at GM in late 1962 to throw umbers and dates off a bit.
The #1175 would fit much better on the first 100 fuel cars or so, but you are the one who has to make the final decision. If you are going to have the car judged, it might do the car some justice to change it. if you are not going to have the car judged, you are the only one that has to live with it. There is not a single person that can tell you for sure that #1175 did not come from the factory, on your car.
Remember, this is a hobby. Each of use gets to decide how far we want to take this numbers matching thing. Ultimately, you are the one who has to decide how much time and money you are willing to put into the car to take it to the level you want it.
Personally, if I were going to judge the car, I would change it for sure. There is a good chance that you are going to run into a few other places, that might be more important to park that money. More important than the number on the plenum.
Bottom line, it is up up you. How correct is the rest of the car? How serious are you about making the rest of the car correct?
Again, remember, this is a hobby.
I hope this helps a little bit,
Monte

[John D.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

Hi Frank and Monte, So Frank you have a Nov 62 Corvette. What is the engine build date?
Let's start out by saying your base plate numbers are right on the money.
#2. Your Nov 62 car would have recessed nozzle blocks. Now I doubt if the plenum would have the bosses sticking out the front though. But you didn't say it had those.
1175 for a Nov 62 may be a tad early on the numbers but the plenum would fly. I have seen recessed plenums (means the area under the nozzle blocks is recessed so you can some of the threads of the 1/4" bolt holding the black plastic nozzle block onto the casting) as late as very early Dec 62.
Monte, Might you be thinking of Nov 63 for serial numbers for 3400-3600.

If the gang here wants to look at a prototype 63 FI unit all you have to do is open the 63 shop manual and check out the FI section. Ignore though the attempt at an artist sketching the flag onto the proto plenum. Some really neat pics there that have confused typical 63 FI owners for an eon. Good luck on your quest for sand cast units Monte. I wish I had #3 back but it has a good home. John

[Monte M.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

John,
Actually you are correct for the most part. But if I am not mistaken during November of 62, they had a pretty good run of high numbers. Like I mentioned before, my car is a November car. When I started doing research, I started with the Nolan Adam's book and call a friend that has been working on the units for years, like yourself.

Next, I just want to say that you (John) would know far, far, far, far, more than I would, but I am just explaining what I ran into when I started looking for my car.

Back to Nolan's book. In the book, the few that are registered in November, give or take a week, are all between 3400 and 3600. I have been told by a number of people that for some reason, there was a release of high numbers for a short peroid of time. The reason I started looking in the first place was because my plenum is in the high 3400's, and I thought it was way off for my car.

John, I would think the average person would say that 1300 to 1600 might fit better, but I was just going off my car and the other ones I had listed for November at the time. Yes, there were a few of the 1300 to 1600 numbered plenums in the mix, but most were higher and I was told that my 3400 was correct for my car.

I actually should have pointed him in the direction of yourself or one of the other very knowledgable people in this field. That was a mistake on my part.
Again, having a car with a very close vin number, I sometimes get tunnel vision and forget that there is usually another answer to any question reguarding a car.

Thank you John for giving him another point of view, but I still stand by the 3400 to 3600 range. Now, I will add, I stand by that and say that there other opitions as well.

John, thank you for clearing that up for me in such a nice manner.
I hope this helps clear up my answer a little bit.
Monte

[John D.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

Hi Monte, Thanks for nice reply. It would not be typical to see such high numbers on a Nov car. That's the nice note that would appear on the owners judging sheets at one of our regionals or nationals.
Maybe speak to our team leader Carlton about the info you have found in your research.
One might wonder why Rochester Products would be shipping such late units to St. Louis for the assembly line while holding back the early ones.
Another way to look at is there are several differences in construction of say a typical early unit and a typical late unit.
For example I once did a seminar on 63 plenums etc. The later plenum with a 3400/3600 did not come from the same mold as an earlier plenum.
The later plenum had more reinforcing ribs than the earlier die cast one. The later unit had featured various chrome items that were not present on an early 62 unit. The later unit had a different top fuel meter bracket. Actually it was the same bracket but the location of the part number was different.
But what really puts a wrench into Nolands survey(taking your word on this Monte as I haven't looked at it for awhile) is the blue print for the 63 plenum. One has to look at the notes on the print and the dates to see when certain changes were made. 3400-3600 serial numbers appeared at the end of the 63 model year.
Now a logical explanation would be that the customer had difficulty with his early 63 unit. If his dealership was anything like the ones in my area the only solution to the difficulty was to replace the FI unit with a fresh one out of the crate from Chevy party aka RP. But who really knows. Thanks for your enthusiam. Keep it up. John

[Frank B.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

Monte and John,

Thank you both for your feedback; It's very helpful. Monte, my car in S.N. 35XX, very close to yours. It's an original L84 convertible. I've been very particular in its restoration. Yes, it's true that Noland's book shows a run of #3400 - 3600 FI units during November '62. It's hard to believe though, as considering approximately 2600 1963 FI vettes, theoretically, FI unit #3600 should be associated with one of the very last cars. It's nice to be supported by Noland's book, though, and I'm sure you have a correct car.

John, thanks a lot for all of the detail in your feedback. My engine build date is November 1, 1962 and my plenum does not have the large extended bosses. They are very cleanly shaved and look very nice. You commented that the base plate is correct as it's dated September. Is there any correlation between base plate dates and the FI unit itself? In other words, were the base plates applied to the plenums during the manufacturing of the FI unit, or were the baseplates later applied at engine assembly? I appreciate your view that my car should have the nozzle block recesses (of course, as that's what I have, right). I, too, believe that my car is early enough to have the recesses, plus, there were fewer of those plenums so more unique. Also, I just read your last posting and your comment regarding the GM replacement plenums is very interesting. Thanks, looking forward to continued replies.

Thanks, Gentlemen

Regards,
Frank

[Monte M.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

John,
I initally did my research on my car back in the late 80's and early 90's. Going to Bloomingtom and then Decater, each year I would look at all the cars and every time I found one close to my vin number, I would write down everythig I could about the car. I still have the notebook I used to take notes in around here somewhere.

I think I recored twenty cars in the November range. Of the twenty cars that were fuel injection, sixteen of them had the higher number on them. I felt that was good enough to think that my plenum in the 34XX was the original one to the car.

I really hate to bring this up, but we all know it has happened a number of times. As time goes by and more and more people are told that 1300 to 1600 is what belongs on a cars, over a twenty or thirty year peroid, that becomes correct because so many people have taken off their original plenums just to go along with NCRS says is correct.

I am not saying that this is the case here, but this is sure a case where this type of thing could have happened. I collected that data over twenty years ago, myself. It was a few years later that I bought Nolan's book, and it seem to validate what I had learned from my research. So, one can see why I might think things may have gotten a little mixed up over time.

On the other hand, i may be way off base here, but for now I am leaving my plenum on my car. If I change it, I am propetuating the problem. What do you think I should do?

I am open to any input you can give me. By now I am sure you have figured out that I do not mind doing a little research to get to the bottom of some of these issues. I thought I had done it twenty years ago, but it loks like I am going to have to revisit that subject. Aren't these forums wonderful. We all get to learn a little more each day.
Wishing you the best,
Monte

[Bob J.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

John,
according to Rochester records, the B revision on 7017375 units started March 19, 1963 with unit number 2953.
That revision data implies all units with a higher serial number than 2953 were BUILT at Rochester later than March 1963 like you said.
Hope this helps, Bob

[Ronald L.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

I think in all this its really good to document what GM did when, from single owner survivor and print data. The issue here as in many cases as Monte points out is 15 years down the road, 1980 for example, people changed these parts because someone said it was wrong, then the car gets judged, blessed and then sold. Now the car is original perfect and numbers matching.

In as much as Nolan did a wonderful job polling for information, there again that data needs deeper scrutiny for the reason above that it was taken from owners that were not generally the first owner and the data set was taken more than ten years after production.

The other thing is what drove the changes and were the changes implemented before or after the print update?

[Bob J.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

The bulliten for the B revision change is pretty clear on when this occured.
" 1963 fuel injection units containing all modifications to date will be marked with a change letter "B" on the inspection tag. This will include all assemblies modified in the field and on all production units built after March 19, 1963, starting with serial number 2953".
Bob

[Monte M.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

Excellent work Bob. I guess I no longer have a leg to stand on. The one thing I have learned about this hobby, is to take everything with a grain of salt.
The real point here is that I pointed Frank in the wrong direction. So for that Frank, I say, "I apologise for that. My intent was to help you figure out if your plenum was correct for your car. My answer for that remains the same, Buy the advise of what you should replace it with, I got advise from some who knows more than I do and suggests that you should most likley be in the 1200 to 1600 range"
I hope this helps.
Thanks for all the input guys. It looks like I may need a new plenum. Anyboby have one in the 1200 to 1600 range? (LOL)
Take Care Guys, and thanks again.
Monte

[Michael G.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

Hi Monte, When I bought the prototype baseplate that you been interested in, it came with plenum #1925, which I seriously doubt was its original plenum. That plenum number may be too late for your car (my late November car has #1567, for example), but its sitting around, we could swap, if you want. Maybe someone can comment on the appropriateness of #1925 for a November car, I don't know.

If it proves to be OK for a November car, email me.

[Monte M.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

Michael,
That is a really fair idea, but my original plenum has had a repair done to it and it is not to the standard of what you or I wouldreally run on our car. The truth is,I guess I really am in the market for a plenum.
Monte

I will send you a regular e=mail.

[Michael H.]

Re: F.I Plunum Serial #1 through #50 Do You Have One?

During the 63 (and 57-62 & 64-65) model year, there were a few complete fuel injection units replaced on cars at Chevrolet dealers under warranty to correct problems. (problems that often had nothing to do with the fuel injection unit) If this occured several months after the original delivery date of the car, that might explain the odd FI unit numbers seen on some cars. It didn't happen often, though.