1969 Air Cleaners, 6423907 & 6423272, what is the difference?

[David L.]

I have what I believe is a 1969 w/SHP 350 Corvette air cleaner ( a photo of the base is enclosed). It came with an engine that had LT-1 valve covers without the drippers (Casting # 3932418 used only on 1969 models). I no longer have the engine.

According to my 1969 Corvette Parts Catalog (Oct. 1969) the 1969 Corvette w/base engine used air cleaner assembly 6423272 and the 1969 Corvette w/SHP 350 engine used air cleaner assembly 6423907. The 1969 AIM also shows part number 6423272 for the base engine on UPC 6, sheet C3 but no part number is listed for the LT-1 engine. The 1969 Camaro Z28 used both air cleaner assemblies in production line (6423907 changed to 6423272 on 10/30/68) according to the 69 Camaro AIM.
The chrome cover and air cleaner element are the same on both air cleaner assemblies so the only difference must be the base.

In November 1993 I bought a new 6423907 air cleaner assembly from Dobles Chevrolet and that base was identical to the base shown in my photo.

Does anyone who the difference between the 6423907 and 6423272 air cleaner assemblies?

Dave

[Lawrence M.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

David, I think on the LT1 base the elbow for the valve cover hose points straight out to the right side valve cover. The 1969 300 hp base points more towards the right rear of the right side valve cover. They use different molded hoses to connect to the valve cover. I think otherwise the bases are the same.

[David L.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

Larry,

Enclosed is a photo of a reproduction base that I got off the internet. I assume you this is what you mean. Over the last 30 years I have seen many of this type of base at swap meets. I just did not know their application. The 1966 300 HP base has a very short elbow and points in a different direction.
Thanks,

Dave

[Lawrence M.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

David, yes the direction that metal tube points is the only difference I noticed. Either base works on my 1969 350HP small block. Why the differnt metal tubes I do not know. Maybe it has to do with the different carbs on the LT1 and 300/350 HP engines.

[Alan D.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

The LT1 engine was not available in 1969 Corvettes. The LT1 came out in 1970. Al Dieterle

[David L.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

The LT1 engine was not available in 1969 Corvettes. The LT1 came out in 1970. Al Dieterle

Alan,

Is there a mistake in the 1969 Corvette Assembly Manual?
UPC LT-1 is listed in the 1969 Corvette Assembly Manual as "V-8 ENG. 350 CU. IN. SPEC. HI-PERF."

Dave

[John H.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

Alan,

Is there a mistake in the 1969 Corvette Assembly Manual?
UPC LT-1 is listed in the 1969 Corvette Assembly Manual as "V-8 ENG. 350 CU. IN. SPEC. HI-PERF."

Dave

Dave -

Yes, there is. The 1969 SHP 350 cu. in. 350hp engine was RPO L-46; no LT-1 until 1970.

[Joe L.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

Alan,

Is there a mistake in the 1969 Corvette Assembly Manual?
UPC LT-1 is listed in the 1969 Corvette Assembly Manual as "V-8 ENG. 350 CU. IN. SPEC. HI-PERF."

Dave

Dave------


The LT-1 was scheduled to be released for the 1969 model year but the option was cancelled before any PRODUCTION cars were built. So, while the option is shown in the AIM, none exist.

However, this brought up an interesting situation for 1969 L-46. If the LT-1 option had been available, then it would have been the "special high performance" 350 and the L-46 would have been the "high performance" 350 (as was the case for the 1970 model year when both the LT-1 and L-46 were available).

Some 1969 LT-1 parts did get into the P&A Catalog. Apparently, the option was not cancelled in time to eliminate all reference of it from the catalogs. So, one will find the 1969 L-46 variously described in the P&A Catalogs as "high performance" and "special high performance". In keeping with usual GM-nomenclature, it should be described as "special high performance", though. When only 2 versions of a particular engine size are available during a model year, the higher horsepower version is usually described as "special high performance"

The confusing year is 1965. Since so many small block engine options were available that year a distinction had to be made between the L-79 and the L-76. So, the L-79 was described as "special high performance with hydraulic lifters"

[Ronald L.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

David, Both bases you mention are from the same die the x188 stamping and the difference noted is as you have found off the internet - that being the angle of the tube. The 69 usage if memory is correct was the 69 Z28 Camaro, following in 1970 with the LT1 Corvette.

I've got a complete asy in the box from that time period. They silk screened the lids back then too, a step in the parts process that would be skipped later in the 70's on service parts

[David L.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

Ron,

According to my 1969 Passenger-Chevelle-Nova-Camaro Parts Catalog (effective April 1970) the 1969 Camaro Z28 used both air cleaner assemblies. GM # 6423272 was used on 1st design and 6423907 was used on 2nd design. HOWEVER, the 1969 Camaro AIM (UPC Z28, sheet A5) shows in the revision record that GM # 6423907 was changed to GM # 6423272 on 10/30/68 which would be just the opposite (???).

The 1969 Z28 AIM drawing shows that hose # 3942518 and connector # 3923260 to be used with the 6423272 air cleaner assembly.

The 1969 Corvette AIM drawing (UPC 6, sheet C3) shows that hose # 3932336 and connector # 3923260 to be used with the 6423272 air cleaner assembly.

My two different 1969 Chevrolet Parts Catalogs (both Oct. 1968) list hose # 3932336 for the 1969 Corvette (exc. 427) and the 1969 Z28 in Gr. 1.762.

Obviously the two air cleaners could not have used the same hose since the elbow in each air cleaner base came out at different angles. Does anyone have a photo showing the difference between the 6423907 air cleaner hose and the 6423272 air cleaner hose? I found a NOS 3932336 hose on Ebay shown in the link below.

http://cgi.ebay.com/ebaymotors/NOS-68-69-70-71-72-Corvette-Air-Cleaner-Vent-Tube-Hose-_W0QQcmdZViewItemQQhashZitem53e8091468QQitemZ360375194728QQptZVintageQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Dave

[Ronald L.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

Dave - yes, that is the hose that makes the bend over to the valve cover for the 350ci C3 cars. It also uses an elbow that is one piece and smaller diameter than the C2 big blocks which obviously goes into the smaller end of that hose you have shown. From pictures only the repro hose looks pretty close to the original in that it has about the same alligator texture as the originals which I have (had or used).

Also - the 66 327 base has the take out to the left side and that base is a one year only wonder.

67 and up there is the added bump that appeared to clear the carb features.

[David L.]

Re: 1969 Air Cleaners, 6423907 & 6423272, what is the difference?

Ron,

I just found some information in my 1968 Camaro AIM (UPC Z28, sheet A5). The 6423272 air cleaner & 3932336 hose were replaced with the 6423907 air cleaner & 3942518 hose as of 11/27/67 in the revision record. The 3942518 hose must be shorter than the 3932336 hose. Since the 3932336 hose is longer GM must have used it as the service hose as it probably must be cut to fit the 6423907 air cleaner.

BTW, I knew about the 1966 "one year only" air cleaner bases (without the extra bump) back in the 1980's.

Dave