[Matt70GTO]

Guys -

I am looking for any/all information on the 1970 Ram Air III engine. Can you recommend a place that has all of the pertinent information?

Thanks.

[unruhjonny]

Try Pete McArthy's book - or as it's affectionatly known in some Pontiac circles as "the Pontiac bible".

You could also try a '70 Pontiac service manual.

[KO]

WS manual transmission, YZ automatic transmission, #12 cylinder heads, 068 cam, 4 bolt main block, 4.120 bore, 3.750 stroke, 6.625 cast connecting rods, nodular iron crankshaft, the only difference between the base 350HP WT manual transmission and the Ram Air III engine is the carburetor and distributor calibrated for the Ram Air and the exhaust manifolds. While Im not 100% sure I believe the automatic transmission engine came with #13 heads.

[Matt70GTO]

Thanks to you both.

Was the 068 cam used both in manual and auto trans? I think that is a hydraulic FT cam, not a roller right?

[unruhjonny]

Originally Posted by KO

WS manual transmission, YZ automatic transmission, #12 cylinder heads, 068 cam, 4 bolt main block, 4.120 bore, 3.750 stroke, 6.625 cast connecting rods, nodular iron crankshaft, the only difference between the base 350HP WT manual transmission and the Ram Air III engine is the carburetor and distributor calibrated for the Ram Air and the exhaust manifolds. While Im not 100% sure I believe the automatic transmission engine came with #13 heads.

I figured it was more about the nitty gritty casting/date codes, and settings for say carburetor and or distributor...

If you wanna go that way;

The 1970 RAIII(L74) & L78 are nearly the same engine, externally the only distinctly different parts were the exhaust manifolds;
They both used the same block casting, head castings, and intake casting;
If you looked closer, the carburetor and distributrs had different part numbers - but htey looked virtually the same.

To the best of my knowledge, all '70 RAIII engines were drilled and tapped for four bolt mains;
All manual transmission RAIII engines recieved four bolt main caps - not all automatic RAIII engines recieved four bolt caps.
All '70 L78/mt engines were drilled and tapped for four bolt mains - but not all recieved corresponding four bolt caps.
I believe some '70 L78/auto engines were drilled and tapped for four bolt mains, but I am unaware of any ever having four bolt caps intalled from the factory.

Both #12 & #13 heads are considered correct;
All RAIII engines were supposed to recieve #12 heads, but some automatic engines recieved the #13 heads;
All manual transmission RAIII(L74) & L78 engines always recieved #12 heads;
All automatic L78 engines recieved #13 heads.
For all intents and purposes, the #12 & #13 heads are the same, the only real difference was that the #13 heads were finished with slightly larger combustion chambers.

All '70 RAIII engines recieved the '068 cam, the one step down L78 recieved a 067 cam.

The following picture is from he '70 Firebird dealer's catalog;
The "standard" engine is the L78 (350hp in GTO), the optional is the RAIII/L74 (366hp in GTO);

[KO]

The 1969 Ram Air III manual and automatics had different cams in early production 068/744, mid year switch to 068 on both

[Kenth]

All 1970 RAIII engines uses #12 heads from factory.
RAIII uses unique distributors and carburetors.
All 1970 RAIII engines uses 4-bolt main caps from factory.
There is bigger differences between #12 and #13 heads than meets the eye.
#12 has about 66cc combustion chambers, longer valve stems, stronger valve springs, no oil shields.
#13 has about 78cc combustion chambers, shorter valve stems, weaker valve springs and uses oilshields.
NO RamAir engine ever uses oil shields from factory.

[KO]

Originally Posted by Kenth

All 1970 RAIII engines uses #12 heads from factory.
RAIII uses unique distributors and carburetors.
All 1970 RAIII engines uses 4-bolt main caps from factory.
There is bigger differences between #12 and #13 heads than meets the eye.
#12 has about 66cc combustion chambers, longer valve stems, stronger valve springs, no oil shields.
#13 has about 78cc combustion chambers, shorter valve stems, weaker valve springs and uses oilshields.
NO RamAir engine ever uses oil shields from factory.

How sure are you about the 12/13 heads because In 69 all manual transmission 400s got 48 heads and the automatics got 62 heads.

Do you know this from direct experience? Did you work at the dealer or GM at the time? or is it just something you read or heard about?

[Matt70GTO]

Thanks guys.

Just bought a '70 Ram Air III Judge. Trying to understand everything about the engine.

My first Pontiac. I have primarily been a Camaro guy (own 2 69's).

[KO]

Im a long time Pontiac guy but I love 69 Camaros. gold w black stripes SS/RS w white houndstooth big block car is what I want

[johnta1]

Welcome, Matt!

That's a good car to start with as a Pontiac owner!

Need some pics and more info on it.

[Matt70GTO]

Originally Posted by johnta1

Welcome, Matt!

That's a good car to start with as a Pontiac owner!

Need some pics and more info on it.

Thanks John. Glad to be a Pontiac owner.

Matching numbers drivetrain. Starlight Black both in and out. Believed to have 48,000 original miles. Believed to have original sheet metal. TH400 trans. Ram Air III (verified the YZ code on block when I saw it in person last week). Looks to have changed a couple of dealer hands over the past year or so. Owner before that owned it 30 years or so I was told. Looks to have been restored a few years ago. I don't trust sellers that I don't know, so I will still need to verify as much of the info above when I get it home.

Having it shipped from Arizona. Won't get it home for a couple of weeks.

Here is a pic of the car.

[Matt70GTO]

And the block stamp......

[Matt70GTO]

And the cool thing about owning a Pontiac is PHS, from what I know. To be able to get copies of dealer invoices/build data is something that Camaro owners would kill for.

[KO]

12 or 13 heads?

[Matt70GTO]

Originally Posted by KO

12 or 13 heads?

Not sure. Wasn't knowledge enough to know the difference when I viewed the car.

Can you tell visually without pulling the valve cover? Is there some sort of casting number on the head that is visible?

[Matt70GTO]

Originally Posted by KO

Im a long time Pontiac guy but I love 69 Camaros. gold w black stripes SS/RS w white houndstooth big block car is what I want

Both of my Camaros are Hugger Orange, one black stripe and one white stripe, both BB (427 and a 396).

[b-man]

Originally Posted by Matt70GTO

Not sure. Wasn't knowledge enough to know the difference when I viewed the car.

Can you tell visually without pulling the valve cover? Is there some sort of casting number on the head that is visible?

You can see the #13 casting number clearly on top of the two center exhaust ports. Most Pontiac heads will have 2 or 3 digits there to ID the head casting.

[b-man]

Here's a thread discussing the 9779068 cam that you may find interesting: http://forums.maxperformanceinc.com/...d.php?t=765522

[Matt70GTO]

Originally Posted by b-man

You can see the #13 casting number clearly on top of the two center exhaust ports. Most Pontiac heads will have 2 or 3 digits there to ID the head casting.

Thanks for the pic. When I get the car home, I will know which heads for sure.