Whats the Difference between "73" 350 and 454 air cleaner?

[James B.]

Is there a difference between a 1973, 350 air cleaner and a 1973 454 air cleaner, i saw something in the judging manual about a flange and offsets but can't seem to find a picture showing the difference? Will the 350 work on the 454?

[Robert R.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

James,

There should be no difference for '73 or '74 air cleaners, small or big block.
There is a change to the '75, with one more cutout (3 vs 2 on the earlier years) on the upper ring.


Bob

[Michael W.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

James,

The distance from the carb to the ignition shielding upper cover is different between a BBC and SBC, the air cleaner upper ring is manufactured differently to accommodate this.

[James B.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

AAAArrrrrrrggghh....I agree there "should be no difference" because that would make things simple, I'm still a little confused, my TIM & JG says there is a black flange that is different between the two, Sounds like Michael is on to something, Can someone send me a comparison photo so I can figure this out.

[Russ S.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

James,

There should be no difference for '73 or '74 air cleaners, small or big block.
There is a change to the '75, with one more cutout (3 vs 2 on the earlier years) on the upper ring.



Bob

There is a difference between 73 SB and BB. The BB ring is offset toward the rear. Also I believe the location of the BB vent hole as well as the pushed in area at the rear of the base is in a different location than a 73 SB

[Peter G.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

It is the metal ring flange that is different. Like Russ said the BB is off set towards the rear of the air cleaner. The reason for the two different rings is that each engine BB and SB sit differently in the engine compartment and in order for the rubber gasket to seal to the underside of the hood for the Cowl Induction these different rings are needed.

[Russ S.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

I did some research back a few years ago on these air cleaners so I will reiterate what I came up with although this is not cast in concrete. 73-74 SB uses a concentric ring BB uses a offset to the rear. SB base has one large dented in area about center in the rear close to in direct line with the distributor. BB base has one smaller dented area an inch to the driver side of the SB dented area. The vent hole is also about 1 inch farther back on the BB than the SB.

75 base is different than 73-74 but the same for SB and BB except that the ring is again offset to the rear. The 75 base has two areas at the rear that are pushed in which touch each other Also the 75 base vent hole is forward farther than either the 73-74 SB and BB (which remember are about 1 inch apart) by about 3-4 inches.(depending on which 73-74 SB or BB you are comparing to)

I suspect 75 rings have different cut-outs than do 73-74 rings due to the crankcase breather hole being 4 inches farther forward. Hope this helps.

Theoretically there should be four different rings for these different applications.
73-73 SB
73-74 BB offset
75 SB
75 BB offset

If any one can add to my findings or have different findings please say so.

[Russ S.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

The 350 will work on the 454 however the crankcase vent hole will be off by 1 inch. I don't know if you would need the vent tube from a 350 to match it up. The other thing I haven't checked out is whether or not the holes in the valve covers on a SB and a BB are in the same location or not.

[Sal C.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

The air cleaner seal flange is shorter in height on the 454

[James B.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

Thanks for all the help guys, I think I will hold out until I can find an air cleaner for a 454, sounds like there are some obvious differences.

[Rich C.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

As stated above, the FLANGES are the only difference between '73-'74 S.B. vs B.B. air cleaners. The BASE is the SAME on both! Same part # in the A.I.M., same part #in the circa '73 parts book, same base! As far as the crankcase vent tube hole??? Again there are two different ones depending on engine. I think confusion starts when people see a car with a replaced air cleaner for example, assuming it was original. I've seen some variation in the 'clearance dent' in the rear, but that 'dent' always looks like it was made by a sledge hammer.

'73 LS-4 454 owned 21 3/4 years!

[Russ S.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

As stated above, the FLANGES are the only difference between '73-'74 S.B. vs B.B. air cleaners. The BASE is the SAME on both! Same part # in the A.I.M., same part #in the circa '73 parts book, same base! As far as the crankcase vent tube hole??? Again there are two different ones depending on engine. I think confusion starts when people see a car with a replaced air cleaner for example, assuming it was original. I've seen some variation in the 'clearance dent' in the rear, but that 'dent' always looks like it was made by a sledge hammer.

'73 LS-4 454 owned 21 3/4 years!

How can you say there are no differences between 73-74 SB and BB bases and then turn around and say there are two different bases (crankcase vent hole) depending on which engine????

[Russ S.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

Lyle, Will you weigh in on this with what you know or believe?

[Rich C.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

How can you say there are no differences between 73-74 SB and BB bases and then turn around and say there are two different bases (crankcase vent hole) depending on which engine????

Well if I was misunderstood, what I MEANT to imply was; THE BREATHER TUBES ARE DIFFERENT DEPENDING ON ENGINE! NOT the vent holes. I've even seen where someone managed to cram the small block tube into the valve cover and base on a big block. I've been looking at pretty much '73's exclusively for about 25 plus/minus years. I don't spout something as gospel unless I can back it up! Do YOU have a '73 A.I.M. and or the '73 parts book?

'73 LS-4 454, owned 21 3/4 years!

Otter Creek Copper Ale, now on tap

[Russ S.]

Re: Whats the Difference between "73" 350 and 454 air cleaner?

I did some research back a few years ago on these air cleaners so I will reiterate what I came up with although this is not cast in concrete. 73-74 SB uses a concentric ring BB uses a offset to the rear. SB base has one large dented in area about center in the rear close to in direct line with the distributor. BB base has one smaller dented area an inch to the driver side of the SB dented area. The vent hole is also about 1 inch farther back on the BB than the SB.

75 base is different than 73-74 but the same for SB and BB except that the ring is again offset to the rear. The 75 base has two areas at the rear that are pushed in which touch each other Also the 75 base vent hole is forward farther than either the 73-74 SB and BB (which remember are about 1 inch apart) by about 3-4 inches.(depending on which 73-74 SB or BB you are comparing to)

I suspect 75 rings have different cut-outs than do 73-74 rings due to the crankcase breather hole being 4 inches farther forward. Hope this helps.

Theoretically there should be three different rings for these different applications.
73-73 SB
73-74 BB offset
75 SB

If any one can add to my findings or have different findings please say so.

As an addendum to this post:
If you go by the parts book for service replacement air cleaner parts which isn't a true indication of what was installed on the line it lists:
73-74 base as 6487577 with no special one for BB
75 base as 8994027
75 base w/K50 (low noise air cleaner) as 8995171 (I haven't heard of this one)

73-75 SB seal flange as 330525
73-74 BB seal flange as 330527
75 seal flange as 354377 (no BB offered in 75)


This info if you can go by it would indicate that 73-74 bases were the same for SB and BB. However if that is the case how do we explain the the 1 inch difference in crankcase vent hole location that I still believe is the difference in the 73-74 SB vs BB base?
I have in my possession 7 of these air cleaners with three different hole locations for the vent filter.