[jhein]

Originally Posted by i82much

IMHO that is still a very conservative cam choice with a wide ratio stick shift, 3.55 gears, 10:1 compression, and fuel injection. Should be a very docile combo. You could easily add another 10 degrees of duration and still have a car your grandma could drive.

Yep.

[Stan Weiss]

This shows a Crane 041, an Elgin 744 and a Sum2802. As you can see the Sum2802 is just about a 744 without the nose cut off.

Stan

[Stan Weiss]

Originally Posted by i82much

i did it with 3.90's and a 28 inch tire for a number of years ... if you want to know what it was like to have a real hot rod in the 70's, it's basically cruising at over 3000 rpm and desperately watching your temperature gauge every time you sit in traffic 🤣

My brothers '65 GTO came from Pontiac with a 4 speed and 3.90:1 rear.

In the late '60s and early '70s my '57 Chevy had 4.56:1

I enjoyed it then, not so much now. lol

Stan

[i82much]

Originally Posted by Stan Weiss

My brothers '65 GTO came from Pontiac with a 4 speed and 3.90:1 rear.

In the late '60s and early '70s my '57 Chevy had 4.56:1

I enjoyed it then, not so much now. lol

Stan

I feel ya Stan! Pains me to say it but at my age sometimes I even think of adding (gasp!) air conditioning to my "hot rod" ...

[unruhjonny]

I hope to be some help by clearing some of the minute details up:

Originally Posted by DogMeister

How's the idle on the Ram Air III cam? Thinking about upgrading the dinky cam and lifters in my 10:1 long-rod 461. Don't mind a bit of lope but not too gnarly. Enough vacuum for the power brakes?

What might be confusing is that there were no "Ram Air III" camshafts persay;
What there was, were two cams that had been used in performance applications for several years prior;
The "HO" cam was the 068 - this one is by a huge margin the most comon performance cam that Pontiac used;
It was in all 1970 RAIII engines, as well as 71-72 455HO - and the same lobe profile and timing as the one used in 73-74 SD455 engines.
The 068 was also used in the earlier "HO" motors, as well as the 1967-1968 RAI and all 1969 RAIII engines when backed by an automatic.

Your 066 is what I might describe as one of Pontiac's "bread & butter" camshaft used between 1965 & 1976 on a ton of engines - this grind was great for torque, but not so much for higher rpm use.

The next step up is the 067;
I would describe this as Pontiac's entry level performance cam - it was commonly used on the performance engines - but never a Ram Air or HO engine.
After 1970, and through to 1976, the highest horsepower (D-port) engines all used this grind.
On paper, this grind is really close to a 066, and I suspect that is why this cam is virtually unobtainable right now - I found one member with an NOS 067 cam, but otherwise, cannot find it.
There is an older Nunzie(?) version of this cam that was at one time called a 067HL - it is essentially the same, but with higher lift.

Next up is the 068 - nuff said.

The next is a 744;
This was for a time the 'Ram Air' cam;
It came on 1966-1969 'Ram Air' (Ram Air I & Ram Air III) engines when backed by a manual transmission;
Some would say (myself included) that this is the best sounding of all Pontiac grinds.
Others would say that this cam is crap because the lobes almost flatten out...

Next up is the 041 - it was introduced with the RAII, and used on it and the RAIV exclusively;
A solid lifter version of this grind preceeded the RAII by seven years.

Originally Posted by mgarblik

The 068 Pontiac cam, sometimes called the Ram Air III cam is a very mild cam. The smoothest, "performance" cam for a Pontiac. Plenty of vacuum, can run with AC, any converter and rear end ratio. Good torque and power to 5000 RPM's. For folks who want a slight upgrade from the ultra smooth 067 run of the mill Pontiac cam, a nice choice. Works in almost any application. Worth 10-15 HP over a bone stock cam.

I wold wholly agree with this post, but just want to point out (as previously mentioned) that the 067 which would be one step up from your current cam is virtually unobtainable.

[Half-Inch Stud]

068 RA III cam in 428-455 would be nice, if it were ping-freeat 10:1.

I'd go "bigger" on Duration (230), and much tigher on LSA (104*) for OPTIMAL broad rpm TQwith great idle and vacuum for PDBs. Prove me wrongk.

Too bad the "tight LSA offerings are 108* off-the-shelf.

[JLBIII]

Originally Posted by unruhjonny

I hope to be some help by clearing some of the minute details up:

Your 066 is what I might describe as one of Pontiac's "bread & butter" camshaft used between 1965 & 1976 on a ton of engines - this grind was great for torque, but not so much for higher rpm use.

The next step up is the 067;
I would describe this as Pontiac's entry level performance cam - it was commonly used on the performance engines - but never a Ram Air or HO engine.

On the 067 cam, I have a 68 Firebird with a 400HO, TH400 and ac. It is my understanding that the 067 was used in the 400HO with TH400 trans and the 068 was used in a 400HO with a manual trans.

[unruhjonny]

Originally Posted by JLBIII

On the 067 cam, I have a 68 Firebird with a 400HO, TH400 and ac. It is my understanding that the 067 was used in the 400HO with TH400 trans and the 068 was used in a 400HO with a manual trans.

interesting.

I don't recall reading (or noticing an instance of a drivetrain that would have had the 068 with a stick being changed to a 067 because of the automatic (ect).

[Kenth]

"068 was in all 1970 RAIII engines, as well as 71-72 455HO - and the same lobe profile and timing as the one used in 73-74 SD455 engines."

1973-74 455SD engines used the same lobe profile and timing as the 744 grind.
Was planned for the 041 cam but did not pass emission test.

FWIW

[unruhjonny]

Originally Posted by Kenth

"068 was in all 1970 RAIII engines, as well as 71-72 455HO - and the same lobe profile and timing as the one used in 73-74 SD455 engines."

1973-74 455SD engines used the same lobe profile and timing as the 744 grind.
Was planned for the 041 cam but did not pass emission test.

FWIW

really - well then I have some egg on my face!
I thought (going off memory) that the original intended SD455 cam profile was the 744, but that failed emission, and it was downgraded to the 068.

Thank you for the correction.

[jhein]

Very informative and interesting article about the SD cam from Rocky Rotella.

https://www.pontiacv8.com/blog/2022/...320-k-camshaft

"McCully shared that the SD-455 with the 308/320 camshaft was compliant with the EPA’s 1973 federal standard, however, it was unable to meet GM’s internal standard. Pontiac was forced to delay the SD-455’s release until engineers could find a solution and recertify it. With customers anxiously awaiting the highly-publicized mill there simply wasn’t time to develop a new camshaft. McCully and team had little choice but to grab the closest proven performance option—a 744-spec camshaft with 301/313-degrees of duration and .407-inch valve lift. The number 493323 (stamped “Y”) camshaft was created for the application, which consequently impacted power output. "

So was the 308/320 cam the "041" profile cam? That's interesting that Pontiac held itself to a more restrictive standard than the feds. That would have been something if they put the 041 in there.

[steve25]

The biggest difference between the 068 and the 744 cam is the added 13 degrees of overlap!

This in and of itself will increase the rpm of where peak torque kicks in by a good 250 to 300 rpm .
If your running the 744 cam today in a under 10 to 1 400 cid motor along with under 3.55 rear gears then your likely not a very happy with your around town drivability and especially with a automatic trans.

[steve25]

Since I had a 68 HO auto Bird I can confirm that the YW motor had the 067 cam and the non RA casting 16 heads a long with the limited carb to knock it down from same darn motor being rated at 360 Hp in the GTO .

This was due to the front office in 67 at GM putting in place the curb weight to HO rule so as to not embarrass the Camaro owners who may have had F body’s with a big block that added another 70 lbs over a Pontiac V8 motored F body.

[unruhjonny]

Originally Posted by jhein

Very informative and interesting article about the SD cam from Rocky Rotella.

https://www.pontiacv8.com/blog/2022/...320-k-camshaft
...

Thanks for the link!!

I like Rocky's articles, but since the demise of HPP, and now me opting out of getting boned on mailing POCI's Smoke Signals (I was told the "international rates" were essentially set to accommodate the Australian memebers) I haven't seen any of his new articles...
I do maintain a POCI membership, but even downloading SS to our tablet has proved to be an excruciating experience..

Originally Posted by steve25

The biggest difference between the 068 and the 744 cam is the added 13 degrees of overlap!

This in and of itself will increase the rpm of where peak torque kicks in by a good 250 to 300 rpm .
If your running the 744 cam today in a under 10 to 1 400 cid motor along with under 3.55 rear gears then your likely not a very happy with your around town drivability and especially with a automatic trans.

I loved it in my fourty-over RAIII (backed with a 3.55 & M22 - probably under geared for a 400 with the M22).

[jhein]

Originally Posted by unruhjonny

Thanks for the link!!

I like Rocky's articles, but since the demise of HPP, and now me opting out of getting boned on mailing POCI's Smoke Signals (I was told the "international rates" were essentially set to accommodate the Australian memebers) I haven't seen any of his new articles...
I do maintain a POCI membership, but even downloading SS to our tablet has proved to be an excruciating experience..



I loved it in my fourty-over RAIII (backed with a 3.55 & M22 - probably under geared for a 400 with the M22).

If you're not able to use that link, I can cut and paste the article and PM it to you.

[JB Eng Wis]

Since its just a camshaft change, I think your choice of the Melling SPC-3 would be your best catalog cam.

[PAUL K]

FWIW a true copy of the 744 cam, commonly referred to as the RA III cam is not availble from any new sources. The Melling copy was changed many years ago.

An authentic 744 cam will have a noticeable rumble in a 400 with headers and 1.65 rockers. It will also have noticeably less bottom end (below 2500) compared to an 068 and considerably more torque than the 041. Milt Schornack thought the 744 was a better cam than the 041. He did a cam shoot out at the track using several aftermarket cams. Nothing ran much better than the 744. Somewhere it's been written that the 744 cam was designed to help Pontiac backed race teams pull strong through the last 200 feet of the quarter mile. The 068 was soft in that area.

Fwiw the aftermarket 224/234 114 LSA 465/488 lift cam that's often referred to as a "hi-lift RA III" has a smoother idle than the 744 cam.

[scott70]

Originally Posted by unruhjonny

interesting.

I don't recall reading (or noticing an instance of a drivetrain that would have had the 068 with a stick being changed to a 067 because of the automatic (ect).

I know the 70 gto 455 came with the 068 cam with a manual trans and the 067 with the thm400. Only diffrerence between the different cams was the transmission choice.

[Formulajones]

Originally Posted by scott70

I know the 70 gto 455 came with the 068 cam with a manual trans and the 067 with the thm400. Only diffrerence between the different cams was the transmission choice.

Kind of interesting how they did that in a 455, yet the RAIII 400 engine of 1970 just came with the 068 cam no matter what trans you chose. Considering the 068 would act much bigger in a 400 and wouldn't even put a dent in a 455.

[unruhjonny]

Originally Posted by PAUL K

FWIW a true copy of the 744 cam, commonly referred to as the RA III cam is not availble from any new sources. The Melling copy was changed many years ago.
...

Any idea how long ago?

The one that is in my YZ engine was acquired in 1998.
I cannot remember the name brand it was, but it was supposed to be a Pontiac 744, and came without a cam card.