63 L84 plenum

[Michael G.]

This pic has been posted here a few times, in various threads, but it was just posted again on CF. It's a pic from an early Motor Trend road test, supposedly (according to Michael Hanson) of a very early, October-built 63 L84 car. What is notable is the lack of recesses under the plenum nozzle blocks, It is my understanding that all early 63s (through at least November or December, 62, as John Degregory has stated here many times) should have those recesses.

Any body have a clue on why those recesses are not on this car, even though this car is so early that it doesn't have flags on top of the plenum lid.? Thanks,

[Carmen R.]

Re: 63 L84 plenum

I don't have an answer and can't really help you out, I just like to say that nothing surprises me anymore when it comes to 63's.

[G B.]

Re: 63 L84 plenum

The initial 7375 plenums were sand cast, and didn't have recesses below the nozzle blocks. You can see these plenums in photos of pilot line FI units on the internet and on my website. The few I've owned have had one or two digit serial numbers on their data plates.

p.s. How the hell could I possibly rate as an "Extremely Frequent Poster"?

[Michael G.]

Re: 63 L84 plenum

Thanks, I figured you or John could edumacate me on this.

Even "Frequent" might be an overstatement, I didn't even know you came here anymore...

[Don H.]

Re: 63 L84 plenum

it could be worse,
you could be called an insane, out of control poster like Mr. McManmon.

[Michael J.]

Re: 63 L84 plenum

it could be worse,
you could be called an insane, out of control poster like Mr. McManmon.

+1......, 13,000 and counting.

But surely it has to do with the number of total posts you have, 1200-1400 seems like a lot, even if you haven't posted in years. I've got like 4300+ over 8 years. and am in the same category.

[Joseph S.]

Re: 63 L84 plenum

I love the photo showing the tech with a cigarette in his other hand. My dad did everything with a cigarette in one hand. Compare those days to today. If you look at a photo from today, everyone has a cell phone in one hand. Ha, how times have changed.

[Michael J.]

Re: 63 L84 plenum

I love the photo showing the tech with a cigarette in his other hand. My dad did everything with a cigarette in one hand. Compare those days to today. If you look at a photo from today, everyone has a cell phone in one hand. Ha, how times have changed.

Very true Joe, things have really changed. Even Zora like to puff around the pits and gasoline fume filled areas, but at least there was a fire extinguisher nearby......

[Michael G.]

Re: 63 L84 plenum

It sure was a different time. Back then, if you blew yourself up, it was your fault, not the tobacco company, Standard Oil, or GM. Today, there would be lawyers lined up drooling for a block if they saw a guy with a lit cigarette anywhere near gasoline fumes...

[John D.]

Re: 63 L84 plenum

Hard to follow the post as it went from FI to smoking. JD used to smoke huge expensive cigars. Haven't smoked since right around the time my pal Dale Pearman died. Not sure when that was.

QT for Jerry. Will a die cast plenum lid fit on a sandcast Plenum? I never tired that trick. Have you? Has anyone else?
On the other hand it appears that is what's in the photo. Will check it out later on my flat screen TV.

As Jerry said the early earlyo 63's pilot line cars had a sand cast plenum. See Noland Adams for a great pic of snad cast unit on a pilot car.

[Michael G.]

Re: 63 L84 plenum

Thanks John, I knew you'd be around before long. Did you ever try to determine when the first recess-less plenums were put on cars or what the serial number of the first one was?

[John D.]

Re: 63 L84 plenum

Mike, I thought I knew the answer to that question but since the world looks at this I am not going to answer and speculate. Reason being is this.
I can tell you this. Just restored two 63's that were very close to one another serial number wise. One has a recessed plenum and the other does not. The one with the recessed plenum is two weeks of so later to the one that had no recessed plenum.
Now that is probably a waste of ink as we all know that's what happends on the assembly line. RP shipped the fuel injections to Flint and they installed them on the engine. Right?
Now here is one you won't read in any books fuel injection fans. Frank Scibica was my little Italian pal. His brother inlaw lived close to me.
Frank used to make fun of NCRS and expecially made fun of me but since he was my idol I did't care. Let me clarify that. Frank did not make fun of NCRS. He loved NCRS. He made fun of the fuel injection judges and gurus.

He told me the fuel injections were a nightmare at RP. Ladies put them together sitting at long tables. Some of them ran and some of them didn't. What ever run and passed the test went out the door. The rest were put on the side and worked on later.
No castings were wasted. Frank called CPA's bean counters. Frank said the bean counters of GM were very upset with RP and the fuel injection business. Today I find that hard to believe as they had to make an absolute fortune selling replacement parts for FI's. But what do I know.
Frank was very sad when the plug was pulled on the 65 fuel injections. Wasn't his fault. Customers quit ordering them as the dealers told them no one knew how to fix them. Hence only 771 '65 real deal fuel cars. But we all know the carburetor was very cheap to install and trouble free compared to FI's and the mechanics could fix them. I went to the GM center in 1961 and 1962. Training center in Pittsburgh area. Mechanics were forced to take the classes. They slept thru them gang. JD was just a kid but did not sleep.

Now I used to think that only the pilot cars had the sand cast FI units. Maybe Jerry Bramlett will chirp in on this. Or others.
Meanwhile I have restored more '63 FI's than I care to remember. I have never seen a sandcast unit on a production Corvette other than pilot cars. But that doesn't mean they didn't exist.
The first 63 die cast plenum fuel injections were ALL recessed nozzle blocks.And they had the big bosses in the front and rear of the plenum. Unless the car had a radio and then the two rear bosses were hacked off with what looked like a chiesel. Very crude.
That's all I know about that Mike.
Lot of recessed nozzle block units coming into my shop the last few years. I love doing them as refreshing with no chrome or little chrome on them.
If Hanson was here he would answer the question. John D

[Mike E.]

Re: 63 L84 plenum

The initial 7375 plenums were sand cast, and didn't have recesses below the nozzle blocks. You can see these plenums in photos of pilot line FI units on the internet and on my website. The few I've owned have had one or two digit serial numbers on their data plates.

p.s. How the hell could I possibly rate as an "Extremely Frequent Poster"?

Jerry,
Must be because your posts are quality rated. Like 10X over many more frequent posters who add very little and keep track of how many posts they have. And I am in no way referring to Terry M, because he also posts informational tech-related posts.

[Michael G.]

Re: 63 L84 plenum

Thanks John, Like most 63 supply issues I'm not sure that there is a correct answer. Oh well, as a 63 owner you get used to this...

[John D.]

Re: 63 L84 plenum

Mike, As far as the serial number of the plenum ID tag the no recess plenums disappeared in late 1500's and early 1600's as I tried to explain above there was a time when apparently both styles were used. Logical isn't it. John