Air Cleaner Base 1970 LT-1

[Patrick B.]

Re: Air Cleaner Base 1970 LT-1

I bought the big block base under the part number 6485239 which included the chrome lid and probably the filter element.

[Warren F.]

Re: Air Cleaner Base 1970 LT-1

Warren:
How does the service replacement LS-6 base in the photo differ from the OE version? I presume the angle of the pipe is the same.

Yes, the tube orientation is quite different as well as the length protruding beyond the base edge plate.

[Warren F.]

Re: Air Cleaner Base 1970 LT-1

Warren,


When you say the part numbers are different, what are those part numbers...the carb conn plate? The Air Clean. Asy? or?

To lock in one of them for you, the carb connecting plate (to use the GM print terminology), and as Dave has provided below is: 6422188

The carburetor air cleaner (GM's term) for the '71 LS6 is part # 6485239, the '70-'71 LT-1 is part # 6423907.

[Warren F.]

Re: Air Cleaner Base 1970 LT-1

I bought the big block base under the part number 6485239 which included the chrome lid and probably the filter element.

That is the correct part # which includes the silencer.

[Edward C.]

Re: Air Cleaner Base 1970 LT-1

My origional 71 LT-1 #1324 points toward the valve cover. Ed

[Kenneth B.]

Re: Air Cleaner Base 1970 LT-1

My two origional 70 LT-1'S FEB/early March are 90 degrees to the firewell. The coupe has only 19,000 & bought from the first owner

[Ronald L.]

Re: Air Cleaner Base 1970 LT-1

Warren, I easily recognize the 6423907, that 3-piece asy has the carb connecting plate as referenced above and has the tube pointing at the valve cover (and has since it was released in Aug 1966). I'll have to go back to the 6423272 Z28 asy again - and look again at the tube, this time next to the 6423907 asy and the 6422188 base (carb connecting plate).


...so now that I had the two side to side, I can see no difference, that is the 6422188 base next to the base in the 6423272 asy.

We need Joe L or Dave K to jump in here with some part number history, what was the change from the 6423907 that was used from 67..68, to the 6423272 that had usage on the 69Z28 plus, and then back to the 6423907 used on the 70 LT1.

[Kenneth B.]

Re: Air Cleaner Base 1970 LT-1

I looked at my70 454 March car & the tube faced back to the fire wall. It didn't look like the tube would clear the valve cover with the low intake so it faced back to the fire wall.
KEN

[David L.]

Re: Air Cleaner Base 1970 LT-1

Ron,

According to my 1965 Chevrolet Parts Catalog (May 1965) the 6422188 base made its debut in Gr. 3.406 and was listed for the 65 Corvette (396). The air cleaner assembly (base, filter, and cover) for the 65 Corvette (396) in the same catalog is 6421816 as shown in Gr. 3.402.

According to Chevrolet Parts History GM # 6422188 was replaced in August 1967 with GM #6423910. GM # 6423910 was then replaced in November 1968 with GM # 6422188. I have never seen a 6423910 base. I have always wondered if the 6422188 bases made in 1965 & 1966 are exactly the same as the 6422188 bases made in 1969 & 1970. It seems that all 327 & 427 Corvette bases made starting in 1967 have an extra "indentation".

I assume that the 6423910 base was essentially the same as the 6422188 base except that it has an additional indentation (for carb. clearance purposes) but that is just an assumption. The 6423910 base is listed in my 1967 Chevrolet Parts Catalog (April 1967) for ONLY the 67 Corvette w/H.D. (427).

Pictured below is a 6422188 base and the cover (bottom side on both) from a 1969 Corvette. This base is IDENTICAL to the base in a NOS 6423907 air cleaner assembly that I bought from Dobles Chevrolet in Manchester, NH, on 11/09/1993 for $70.88 (list price was $78.75). I still have the receipt but I sold the air cleaner asm. When installed on an engine the tube points directly toward (and perpendicular to) the valve cover. At Summer Carlisle (July 1991) on space # IF6 I made a sketch of a NOS 6422188 base for sale for $40 (box dated 1-4-88) and it is IDENTICAL to my 69 Corvette base.

I assume the base on a 6423272 air cleaner assembly is the same as the 6423907 air cleaner assembly EXCEPT that the tube is rotated 45 degrees so that it would tend to point toward the firewall when installed an engine.

Dave

[Patrick B.]

Re: Air Cleaner Base 1970 LT-1

Yes, the tube orientation is quite different as well as the length protruding beyond the base edge plate.

Warren: I'm confused about your reply. Are you saying that an original LS-6 base does not have the tube pointing toward the valve cover opening like the service replacement LS-6 base in my picture 3? Also I don't know how you can evaluate how far the tube protrudes beyond the base edge plate from picture 3 with the hose covering the tube. Pictures 1 and 2 show the tube better but they are of the LT-1 base not the LS-6 base.

[Ronald L.]

Re: Air Cleaner Base 1970 LT-1

Dave,

Yes the base plate 6422188 started in 1965 without the famous 5 o'clock bump. That tool was sent out in Aug 1966 and modified to add in that bump but was not back in time for 67 SOP, some early 67 327 cars have the 66 design base plate.

And its the stamping I refer to, the base plate asy 6422188 was punched on the pass side and tube added.


Like I said earlier, I laid the 66 427 6422188 original base along side the base from the 6423272 asy and other than that bump, I cannot find a difference.

[David L.]

Re: Air Cleaner Base 1970 LT-1

Dave,

Yes the base plate 6422188 started in 1965 without the famous 5 o'clock bump. That tool was sent out in Aug 1966 and modified to add in that bump but was not back in time for 67 SOP, some early 67 327 cars have the 66 design base plate.

And its the stamping I refer to, the base plate asy 6422188 was punched on the pass side and tube added.


Like I said earlier, I laid the 66 427 6422188 original base along side the base from the 6423272 asy and other than that bump, I cannot find a difference.

Ron,

How do you know that your air cleaner assembly is GM # 6423272? Is it NOS in the box?

As I understand it your 1967 Corvette (427) 6422188 base does NOT have the extra "indentation" (or "bump" as you call it). Based on this I assume that there is therefore a "1st design" 6422188 base WITHOUT the "bump" as well as a "2nd Design" 6422188 base WITH the "bump". I can buy that as sometimes GM does unusual things as the 6422188 was "reborn" in November 1968 as per Chevrolet Parts History.

I have found that a "2nd Design" 6422188 base is identical to the base on a 6423907 air cleaner assembly. As mentioned before I have seen a NOS 6422188 "in the box" as well as owned a 6423907 air cleaner assembly "in the box".

Now that I am totally CONFUSED what is the difference between a 6423272 air cleaner assembly and a 6423907 air cleaner assembly? If the lid, filter, and base are the same why is there 2 different part numbers?

Dave

[Ronald L.]

Re: Air Cleaner Base 1970 LT-1

Dave,

On the ..272, yes NOS signed sealed & delivered.


Couple of corrections...

its a 1966 427 base and its the real deal.

The only 67 cars I have seen and well documented here as well, are 327 cars. I don't believe the 67 Holley's would clear and thus the need for the bump.

Keep in mind, that base plate stamping was ONE die popping these out by the hundreds per hour. It actually was more, a blank and draw, a restrike and then a punch. After that it went through a hemming machine.

It was only at the punch station a 327 becomes different than the 427, or where other holes would get punched to make smog car variations of this base 212 design.

[David L.]

Re: Air Cleaner Base 1970 LT-1

Ron,

So what is the difference between a 6423272 and a 6423907 air cleaner assembly? If the cover, filter, and base are the same what is the difference, the type of black paint?

Dave

[Ronald L.]

Re: Air Cleaner Base 1970 LT-1

Dave,
For sure the silk screen was different from 66 67 - to this 69 part. I really expected the tube to be pointing rearward, that fact it is not is a mystery.

The paint is the same, the mono rail never changed, the paint tanks never changed, nothing of the process changed until it was torn out and the building torn down.

Perhaps they got these all mixed up with the difference being in the tube orientation. That would be easy to see happening. Later on, Service then determined both work, just using a different hose routing