[johnta1]

Where you are technically incorrect, is that some 1970 L74 engines were assembled using the same short block as the L67/RAIV engines.

This should be that some WS coded engines used the 9799915 BLOCK but still had cast pistons. These blocks were also ground off '4' and stamped '5' in its place. (also had the 068 cam in it)
These also seem to have been in the Judge and not TA?

[Half-Inch Stud]

GTO-Based & F-Body based Ram Air answers are fair game, yet "Marketing comes to my mind.

390HP 428 HO 4-bolt Caps, Long Branch, RA-III heads, 068 cam, same iron Intake, Stout TH400 ( or equal 4-speed) and mandatory Posi ( even Judges has open Diff)

Mucky; Figure that any PMD with a factory Class 3 Tow Package probably has an HO engine + Posi (cooling fan, Radiator) that exceeds most Ram Air cars

[unruhjonny]

Originally Posted by johnta1

This should be that some WS coded engines used the 9799915 BLOCK but still had cast pistons. These blocks were also ground off '4' and stamped '5' in its place. (also had the 068 cam in it)
These also seem to have been in the Judge and not TA?

huh... I thought I read quite the opposite.

[johnta1]

Not for the RA III engines. Why they used the 979991'5' block for some RA III is unknown as far as I know.
They also seemed to be from Hxx9 to Jxx9 cast blcoks. Possibly they had an excess of 915 blacks and used them for the WS/YZ engines. I have one of those blocks that came out of my 70 Judge. It had all the parts of a normal WS engine, cast pistons and 068 cam.

I would say the 'recipe' for the engine makeup is based on the WS/YZ codes and not on the 9799914/15 block.

BTW, if bought over the counter, the RA III would still have the cast pistons.

[73T/A]

The name Ram Air III gets used often in describing 69-70 Judges and Trans Ams with D port engine.Did Pontiac officially ever use this name in sales brochures or marketing material to designate this particular engine or was just adopted by the general public.If we compare a a standard 1970 GTO 350 HP 400 WT code engine to the so called Ram Air III engine the only real differences are the Ram Air exhaust manifolds and the functional air breather.Both engines use the same number 12 cylinder heads and intake manifold.Also both engines use the O68 camshaft.

[unruhjonny]

Originally Posted by 73T/A

...If we compare a a standard 1970 GTO 350 HP 400 WT code engine to the so called Ram Air III engine the only real differences are the Ram Air exhaust manifolds and the functional air breather.Both engines use the same number 12 cylinder heads and intake manifold.Also both engines use the O68 camshaft.

Sorry, you are mistaken.

WT(L78) to WS(L74) differ by:
Camshaft: WS 068 / WT 067
Carburetor: WS 7040273('573-CA) / WT 7040263('563-CA)
Exhaust manifolds: WS 'ram air' castings / WT 'standard' castings
blocks: WS* 4-bolt mains / WT* 2-bolt mains (* = this was how it was supposed to be)

Actually as I have read and understood it, PMD did a service to people who ordered the standard 400-4bbl in the A & F bodies;
I believe I read it described as "this years hot ticket" or something to that effect;
PMD said to have intentionally put the "hot" (D-port) Ram Air heads on these engines.

As a point of comparison, for 1969 the L78 did NOT share heads with the L74.

[73T/A]

Not mistaken on the exhaust manifolds.I mentioned that one of the differences was the Ram Air exhaust manifold's.Looking at Pete McCarthy’s book he list the 1970 GTO engine(WT) with manual transmission getting the 068 camshaft.He shows the automatic equipped GTO getting the 067 camshaft.

[73T/A]

Ok,looking at both of Pete McCarthy’s books.Pontiac Musclecar Performance Book shows 067 camshaft for standard GTO engine manual transmission.Pontiac Racers High Performance Book shows 068 camshaft for manual transmission GTO.We have a discrepancy between both sources.

[unruhjonny]

after mid 1969 (model year) there were AFAIK no manual vs auto camshafts;
the 068 was always an HO cam, the 067 was the bread and butter performance cam.

WT = 067
WS = 068

[unruhjonny]

you made me look;
I’m not seeing any suggestion that the WT had anything other than the 067.
I believe you are mistaken.

It happens to us all though

[73T/A]

Originally Posted by unruhjonny

you made me look;
I’m not seeing any suggestion that the WT had anything other than the 067.
I believe you are mistaken.

It happens to us all though

No mistaken just reading what is in black and white in this particular Pete McCarthy’s book.Says 068 for manual GTO.Flag note #8 notes 067 for automatic GTO.

[73T/A]

As mentioned earlier both of the Pete McCarthy’s books show to different cams for GTO with manual transmission.

[Kenth]

There are actually 3 different camshafts for the 1970 M/T and A/T GTO engines.
067 for 350 hp. STD.
068 for 366 hp. RAIII.
041 for 370 hp. RAIV.

FWIW

[steve25]

Here’s the info from the 1970 sales brochure.
In terms of a 400 GTO there where only 3 Cam choices

The 744 Cam was deleted as a 400 package option by mid 1969.

[unruhjonny]

Originally Posted by 73T/A

As mentioned earlier both of the Pete McCarthy’s books show to different cams for GTO with manual transmission.

Just circling back to this, because I am earnestly trying to help, and to clear up any confusion.

It appears as though your images are all from Pete's 'Racer's handbook';
This book was printed in 1981 - I have a copy of that one too, but rarely reference to it because I don't bracket race.

This book you are citing obviously has errors.

I shared images from the 1970 Pontiac service manual and Pete McCarthy's "bible" - both show the 068 was the L74 cam only.

If it matters, my book "Musclecar Performance 1955-1979" has a print date of 1989, and is the third printing of the fifth edition.

Also, we need to understand that authors make errors.
Just because you can find a print source, doesn't mean that it's fact.
Even model year (pre-production) literature can have errors.

For the 1970 model year:
L78 = 067
L74 = 068

period.

[73T/A]

Sure there can be errors in any printed publication or advertisement whether Pete’s or PMD.
1969 it shows 400 manual WT-068 cam
400 automatic YS-067 cam


So 1970 PMD dropped the 068 from the 400 WT engine.Thats interesting.

[73T/A]

1969 Looks like the both the standard WT engine and WS Ram Air engine used the 068 cam.After the 744 was dropped mid year on the WS.