[glhs#116]

OK. So first of all I clearly need a little schooling on the year by year air cleaner changes. I've got a 1971 Trans Am with the original 455HO engine, intake and a nearly correct carb. The car came to me with a stock looking air cleaner with the two tabs for attaching the shaker with two wing nuts but it's a single snorkel and I think the original should have been dual snorkel. No matter, everything fits and hooks up where it should. The car was HEI converted by a previous owner and I'm not sure if maybe the air cleaner was changed at that time for better fit with the bigger distributor?

For the first part of its life I had the car in a desert climate and cooling and cool air were my primary concerns. I have the shaker completely open and in fact used to block off the single snorkel so that the air cleaner had to feed entirely from the open shaker scoop.

Anyway, fast forward to now as I’m trying to inch my way to better drag strip times on my local 1/8 mile track. Out of curiosity last weekend I unblocked the snorkel and with no other changes picked up a mile an hour on the top end. So that told me that the open shaker wasn’t enough to feed it. Indeed, there isn’t a very big gap that air can move from the shaker into the air cleaner. But having seen that the snorkel was needed my next obvious question is: Is the single snorkel a restriction to a big 455 with a reasonable cam and eheads? And then the next question is what’s the next best way to increase inflow, since a quick look confirms that dual snorkel air cleaners go for silly money.

Sam

[Schurkey]

Plumb an air-cleaner restriction indicator into the clean side of the air filter. Run the engine WFO, max RPM. See what the results are.

If I wanted a dual-snorkel air cleaner, I'd visit the Treasure Yard, find an air cleaner with a sexy snorkel, and then weld/braze/rivet the snorkel to my air cleaner housing after cutting an appropriate hole in it.

[HO Kenny]

The single snorkel air cleaner housing would be from a 1970 ram air 3 trans am. I would in now way cut the rather rare and expensive 70 trans am air cleaner housing. I believe reproduction dual snorkels are available.
The 1970 ram air 4 and the 1971 and 72 455 HO would be dual snorkel.

[Skip Fix]

It all depends if you are running an air cleaner element. Even a K&N makes a significant impact in flow you can measure at the track.In fact one night dialing in my first 455 roller in the 78 TA we jetted it for the air cleaner in. Pulled the element out-I had made a cage like the L88s to hole the base down. Doing a dry hop after my burn out lean popped out the make of the scoop at me at night! With an open 78 scoop and the smaller round snorkel base my car has run 10.90s @ 125 no element. With more weight and an element runs 11.50s @117 in the Texas heat all day long.

Flow numbers
http://forums.maxperformanceinc.com/...r+cleaner+flow

[Drag Star Le Mans]

Get yourself a K&N X-Stream airflow air cleaner lid. This should help out. Nobody will know it's on there with the shaker mounted.

[Skip Fix]

Some folks think the filter lid interrupts the airflow into the carb.

[jhein]

Seems hard to believe that the carb could flow more air than a wide open shaker and a single snorkel. I have my shaker flap installed but it's just hanging loose, not connected to anything. When I go to WOT, the airflow pulls it open about half way, that's with a single snorkel 70 air cleaner assembly.

[Skip Fix]

Is the snorkel open also?

[glhs#116]

So, there's actually not a great flow from the shaker to the air cleaner in my setup "as delivered".

My air cleaner


What I decided to do was address the way the shaker opening almost totally closes off the gap where air could come in. I was going to bend the whole lip in at the back but decided to leave the places where the spot welds were

View looking in the scoop (after mod)


View with scoop removed (after mod)


Sorry I didn't get a before picture but you can see from the bits I left how little the stock gap is. Not sure if this was different in later years. There's a small area near the front where a bit of air gets through. The sides can't. I figure that area I opened up is at least half another snorkel's worth. Yes, the snorkel is staying open now after I discovered the restriction.


Sam

[jhein]

Man, that is tight. I just went out and looked at mine. I have about 1/2" around the back area where you did your modification. As you go further around it gets even tighter. I can get a finger in between the shaker and the ledge of the lid. From the look of yours, before your modification it doesn't look like you could do that. So really, that gap between the inside of the shaker and the air cleaner lid is really the functional opening of the shaker. That's an eye opener.

[Skip Fix]

Yes they are tight in there! But again 10.90s @124 in a 3750lb car must allow some air!

[track73]

I can't believe how much people want for used 79 Pontiac TA air cleaner bases. most want $600 or more.

[jhein]

Originally Posted by Drag Star Le Mans

Get yourself a K&N X-Stream airflow air cleaner lid. This should help out. Nobody will know it's on there with the shaker mounted.

I've seen those before but didn't think I needed one. Now I have one on the way. Thanks.