Author Topic: 77-81 SHAKER IDENTIFICATION  (Read 721 times)

Grand73Am

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77-81 SHAKER IDENTIFICATION
« on: April 12, 2018, 11:05:06 PM »
Since I've answered some shaker questions on TAC in the past, it's been requested that I start a new topic, telling what I know about 77-81 shaker identification in one place. First of all, I don't claim to be an expert on the subject, but I have some info and pics that can help you identify the different shakers used during these years, so you'll know what to look for when hunting for a shaker for your situation. You can't always trust what the decals say on the shakers. Sometimes sellers don't even know what they're selling, so you need to know yourself. So, here goes.

First thing to realize is that the shakers, and the air cleaners they sat on, were different for every kind of engine that was used in 77-81 Trans Ams. So you have different shaker setups for the 400 Pontiac, 301 Pontiac, 403 Olds, and 305 Chevy. From late 77 through 1981, the shaker scoop for all those engines was the same part(except for a small difference in the 305 scoop which will be discussed later). So, you can't tell what engine the shaker is for by just looking at the scoop, since they're all the same (except 305). In order for the same shaker scoop to fit to the hole in the Trans Am hood for the different engines, they used an "adapter" plate. That's the metal plate that's riveted to the bottom of the shaker scoop. The plate adjusts the scoop's position so it would be centered in the hole in the hood, and be at the correct height, for the engine the scoop was being used on. So, a 400 has it's own adapter plate(works for 350 and 455 Pontiac too), 403 has it's own adapter plate, as does 301 and 305. So, to be able to tell what engine a shaker is for, you need to know what the adapter plate looks like. That will be covered later on.

Because the scoops are the same, if you have a scoop on your car that's already painted to match your car, but you want to do an engine swap, you can change the adapter plate to suit the new engine and be able to keep your scoop. You can remove the adapter plate by carefully grinding and/or drilling the rivets off. There may be some factory sealer that you have to scrape or sand off of the shaker to smooth the surface. Then replace the adapter with an adapter that suits your new engine. It aligns with the same rivet holes. You could just use some small pan head screws and nuts to fasten it. Or if you want it to look original, you could use some small bolts that have rivet-looking heads,which attach with small nuts, and they'll look like original from the top. After fastening, I put a dab of glue on the nuts to prevent the possibility of loosening. Some lock-tite would do the same. I used the small rivet bolts used for 55 chevy grilles, sold by 55-57 resto places, but the pack only contains 7 rivets, and there are 8 holes, so I had to buy 2 packs. Below is a photo of the rivet head bolts. I just found this source for them where they sell them individually for 75 cents each, which would be much cheaper: http://bobsautomobilia.com/hardware/rivet-head-bolt-10-32-x-1-2-long-1924-30-.-rb-10/

Untitled by grand73am, on Flickr

Some people have reported that they've been able to re-position their original adapter on the shaker by drilling new holes and moving it, so it will line up with the hood when it's on the new engine. If you go that route, you also have to consider the height of the adapter, since they are different heights for different engines, because the engines have different heights, so some modification to the height of the adapter might be needed too so the shaker doesn't hit the hood. For example, if you use a 301 adapter on a 400 engine, the shaker will sit too high, because a 301 adapter is taller(due to the shorter engine) than the 400 adapter plate.

Also, the air cleaner bases are different for each engine, and that will be covered as we go along as well.

So, 1977 was the year they changed from the more rounded style of the 76 and older shakers to a new style of shaker scoop. The new 77 shaker style was a "low-rise" shaker. It can most easily be identified by the prominent ridge down the center of the scoop. And it's shorter in height than the later shaker scoops, so it didn't protrude as far above the hood as later ones, as you can see in the picture below of a 77 Trans Am. The low-rise shaker didn't last long, because later in 77, another new style shaker scoop appeared which was taller and didn't have the prominent ridge down the center. So, the low-rise shaker is sometimes called the "early 77 shaker". Here's a picture of one, and the air cleaner that was with it. I believe it's the wrong air cleaner for a 77, since I've read that all 77's used the "trumpet" style snout. But more about that later. But it is a 400 air cleaner base. Notice the ridge down the center of the scoop, and the short height. Also notice the adapter plate has 2 pointed protrusions inside it. That's the indication of a 400 adapter plate. You'll see more examples of that later. And the large carburetor hole in the air cleaner base is centered, which is how the 400 air cleaners are. They also have a small hole just forward of the large carb hole, which is for the bowl vent of a Pontiac Q-jet, another clue to a 400 air cleaner:

77 low rise 400 shaker a by grand73am, on Flickr

77 low rise 400 shaker b by grand73am, on Flickr

77 low rise 400 shaker c by grand73am, on Flickr

And here you can see how the low-rise shaker doesn't rise very high above the hood:

77 TA with lowrise shaker a by grand73am, on Flickr

Next came the later 77 through 1981 style of shaker scoops. The 400 shakers have the adapter plates with the 2 pointed projections within the ring of the adapter. The points are how you can identify the 400 shaker. The adapter plate ring is approx. 16-3/4" outside diameter. Below are some more pics of those:

IMG_6699 by grand73am, on Flickr

The 400 engine had 2 different shaker air cleaners. There was one with a long, tapered snout, sometimes referred to as the trumpet style. It was used on the standard 180 hp L78 400 in 1977 and 1978, and on the optional 200 hp W72 400 in 1977. The other air cleaner had a different snout that was shorter and wider with an oval opening. It was used on the 220 hp W72 400 in 1978 and 1979. The photo below shows a side by side comparison of the trumpet snout and the wider, oval snout. They both work on 400 engines(and 350 or 455), but the wider, oval snout air cleaner is the more desirable/valuable of the 2. Notice the carburetor holes are centered in the air cleaner bases, and they both have the small holes for the Q-jet bowl vent tube. The air cleaner diameter is approx. 16-1/2" outside diameter.

IMG_2593 by grand73am, on Flickr

Here are some more pics of the 78-79 400 W72 air cleaners, with the plastic adapter for the inlet. It adapts the oval snout to accept the round acordian air inlet hose. And here's a pic of the setup on a car:

air cleaner w72 c by grand73am, on Flickr

air cleaner w72 b by grand73am, on Flickr

Air Cleaner W72 a by grand73am, on Flickr

SANDEN AC COMPRESSOR ON 400 ENGINE by grand73am, on Flickr

Next is the Olds 403 shaker. The distinguishing characteristic of the 403 shaker is the adapter plate that is offset quite a bit. The carburetor hole in the air cleaner base is also off-center. Below are pics of both. Notice how the adapter plate has a very wide flange toward the front of the scoop. And in the picture of the car, notice how the adapter plate extends beyond the front of the scoop, indicated by the red arrow. Also when using a 403 shaker, the air cleaner stud is not straight. It's crooked, as seen in the photo below(credit to Aus78Formula for that pic). The 403 adapter ring is approx. 16-3/4" outside diameter, and the air cleaner is approx. 16-1/2" diameter :

SHAKER 403 by grand73am, on Flickr

403 air cleaner base by grand73am, on Flickr

79 TA nocturn blue-tan u by grand73am, on Flickr

Untitled by grand73am, on Flickr

And here's another 403 TA, just because it looks good:

403 in car by grand73am, on Flickr


Next is the 301 shaker. The adapter ring is smaller in diameter than the 400 and 403. I don't know the measurement, because I've never had one to measure. It doesn't have the pointed projections within the ring like the 400 does. The air cleaner is distinctive due to the concentric grooves in the base.

engine4 by grand73am, on Flickr

air cleaner for 301 c by grand73am, on Flickr

a by grand73am, on Flickr


Next is a 305 shaker. It's has a scoop that is a little bit different, which makes it easy to tell it's for a 305, just by looking at the scoop. The scoop has a "bump" sticking out of the passenger side of the scoop, as seen in the photos below. It also has a smaller diameter adapter ring than the 400 or 403 adapters. The air cleaner has a snout that faces the passenger side when installed. This shaker is desirable when using any small block Chevy V8 in a Trans Am, most common being a 350 Chevy swap.

305 shaker by grand73am, on Flickr

305 shaker a 5-15-17 by grand73am, on Flickr

305 shaker 1 by grand73am, on Flickr

Next is just some miscellaneous info that you might find interesting.

Here's an illustration of the shaker seals. There's supposed to be a rubber seal on the bottom of the adapter plate, so that when the adapter is sitting on the air cleaner and is clamped down, it seals and also help prevent the shaker from slipping and moving around the air cleaner base due to engine vibration.

SHAKER SEAL INSTALL 80 ASSY MANUAL by grand73am, on Flickr

A SHAKER SEAL by grand73am, on Flickr

Also many people wonder how the back of the shaker should be painted, since all these years later, the original paint has deteriorated. From what I've seen in pictures of TA's when they were new, I believe the rear fake vent area should be semi-gloss or satin black. Below is a pic of an NOS shaker scoop. It came from the factory in black primer. I believe the rear area was masked off and the rest painted body color. Then over the years, the black primer on the fake vent area wore off, exposing the original lighter colored fiberglass material, which is why some people think it was a different color there. But, I've looked closely at several of my shakers and found tiny remnants of the original black primer in the grooves, which is more proof that it was orginally black in that arera.

scoop for pontiac NOS on ebay d by grand73am, on Flickr

IMG_0806 by grand73am, on Flickr

So, that's all I got. If you have more info you'd like to add to this thread, feel free.






« Last Edit: April 13, 2018, 07:16:05 AM by Grand73Am »
Steve F.

Jack

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Re: 77-81 SHAKER IDENTIFICATION
« Reply #1 on: April 13, 2018, 03:28:24 AM »
Nice write up Steve, thanks for posting and hopefully it will turn into a sticky.




Regards, Jack

Grand73Am

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Re: 77-81 SHAKER IDENTIFICATION
« Reply #2 on: April 13, 2018, 07:20:27 AM »
Thanks Jack! I remembered something else, so I added a little additional info that starts at paragraph 3 if you'd like to take a look.
Steve F.

Warren Seale

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Re: 77-81 SHAKER IDENTIFICATION
« Reply #3 on: April 15, 2018, 09:01:18 AM »
Original owner of my 79.  The fake grill should be flat black (like black primer).  The paint on mine is still original and intact.
« Last Edit: April 15, 2018, 09:02:58 AM by Warren Seale »
79 T/A,WS6,403,A3
96 T/A,WS6(#1344),M6
72 442,W30,A3
96 Vette Grand Sport convertible,F45,LT4,M6
06 Vette convertible,Z51,M6

Grand73Am

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Re: 77-81 SHAKER IDENTIFICATION
« Reply #4 on: April 15, 2018, 09:05:12 AM »
Original owner of my 79.  The fake grill should be flat black.  The paint on mine is still original and intact.

Excellent! Can't get more definitive than an original owner with an original example. Thanks for adding to the info.
Steve F.

Re: 77-81 SHAKER IDENTIFICATION
« Reply #4 on: April 15, 2018, 09:05:12 AM »

Aus78Formula

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Re: 77-81 SHAKER IDENTIFICATION
« Reply #5 on: April 15, 2018, 06:21:47 PM »
Is it black over the shaker paint, or is it black base masked off before paint? With the 77-81 Formulas the scoops are already in black with a peel off panel for after final painting in to body colour.

Formula Hood scoop NOS 2 by Aus78Formula, on Flickr

Grand73Am

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Re: 77-81 SHAKER IDENTIFICATION
« Reply #6 on: April 15, 2018, 07:08:24 PM »
That's interesting about the Formula scoops, and would certainly be the efficient way to do it.

The photo of the NOS(new old stock) shaker scoop in my post is a pic I saved from an eBay sale. It shows the scoop started in what I would assume is black primer, but has no masking on it like your scoop has. Whether it didn't come with masking, or the seller removed masking from it for the photos, I can't say. Either way, the fake vent area had to have been masked, and the rest painted with body color, leaving the flatter looking black primer on the vents once the masking was removed. Being just black primer, which was likely lacquer primer, it wore off more easily, creating the effect we usually see on them now.
Steve F.

Aus78Formula

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Re: 77-81 SHAKER IDENTIFICATION
« Reply #7 on: April 15, 2018, 07:56:23 PM »
In later years of producing spares they may not have bothered, but I can imagine production line would have something pre-cut to mask, rather than the shop boy sitting all day with masking tape around the curves!
i actually copied the Formula mask onto some templates that can be traced onto tape for when I need some masked in one hit.

Grand73Am

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Re: 77-81 SHAKER IDENTIFICATION
« Reply #8 on: April 16, 2018, 08:11:26 AM »
In later years of producing spares they may not have bothered, but I can imagine production line would have something pre-cut to mask, rather than the shop boy sitting all day with masking tape around the curves!


That makes sense  :-) .
Steve F.

Jack

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Re: 77-81 SHAKER IDENTIFICATION
« Reply #9 on: April 16, 2018, 08:28:47 AM »
Congrats Steve your post just got pined :D




Regards, Jack

Grand73Am

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Re: 77-81 SHAKER IDENTIFICATION
« Reply #10 on: April 16, 2018, 08:46:21 AM »
Thanks! It's all your fault  :-D .
Steve F.

Re: 77-81 SHAKER IDENTIFICATION
« Reply #10 on: April 16, 2018, 08:46:21 AM »
You can help support TAC!