[67Fbird]

Since I could NOT find this online easily...I had to go dig up MY original card.

[67Fbird]

argh...me and pics do NOT get along!

[67Fbird]

[steve25]

I finally figured out how to correct this rotation thing in my phone when this happens.
Go into your photos and go to the photo you want to correct.
Next go to the top right and hit edit.
Give that a sec to load and then hit the square rotation box on the bottom next to revert.
Give this a sec to load, now go up top on the near left to the square box with the rotation arrow, the hit that to spin the photo around 360 degrees, YES back to where you started.
Now your done and when you post it on this site it will be correct.
Lastly hit done on the bottom right.

Why the heck this and other sites do this, but yet when I post for instance the same photo on Facebook it loads right I have no idea why!

[steve25]

Please note that the factory springs for the RAIV motors provide the needed 123 psi on the seat, not 90 as on that Cam card, also 262 psi of open pressure is right on the edge of getting the motor to 5800 rpm if you ask me, no less a valve float rpm of 6500, at least with a big 2.11” intake valve!

The RAIV factory springs also provided over 300 psi of open pressure at .519” lift made by the 1.65 rockers.

[67Fbird]

things that make you go ...hmmmm...was right on my phone...email...computer...oh well.

[Tom Vaught]

Originally Posted by steve25

Please note that the factory springs for the RAIV motors provide the needed 123 psi on the seat, not 90 as on that Cam card, also 262 psi of open pressure is right on the edge of getting the motor to 5800 rpm if you ask me, no less a valve float rpm of 6500, at least with a big 2.11” intake valve!

The RAIV factory springs also provided over 300 psi of open pressure at .519” lift made by the 1.65 rockers.

Pretty sure that the RA-IV camshaft was first offered in mid year 1968 in the GTO, and then later offered on the vehicles listed below:

"When Hot Rod magazine tested a Ram Air IV-equipped Trans Am, it did the quarter mile in 14.1 seconds, breaking 100 miles per hour in the process. Introduced in the middle of the 1968 model year, the engine was available in the GTO, Judge, Firebird and Trans Am through 1970."

So the Crane/Pontiac/Universal Camshafts (Universal Camshafts made the cams before Crane was involved.)

The cams were first built and supplied to Pontiac with the 1.5 ratio rocker arms in 1968 1/2.
I bought 10 of the RA-IV cams from Universal in May of 1970 for $37.20 each when Pontiac Dealers Parts guys were wanting $254.00 for the camshaft in 1970 dollars. I sold the cams for twice what I paid for them and the Pontiac Buyers very smiling from ear to ear.

So the point being Steve25, the camshaft card was not wrong for 1968 1/2 Pontiac 400 engines.

Tom V.

[Kenth]

The Crane 041 cam card seems a bit off since they measured 90lbs open spring load @ 1.578" installed height.
Also 99840 is a single spring.

In 1968 RAII inner springs #9794044 was 39-43 lbs @ 1.726" and outer springs #9794045 76-80 lbs @ 1.776" installed height.

In 1969-70 RAIV inner springs #9796789 was 39-43 lbs @ 1.782" and outer springs #9796790 76-80 lbs @ 1.818" installed height.

FWIW

[Tom Vaught]

For sure there are some differences/issues with that Crane Camshaft card.

I am trying to remember the applications for the single spring on the engines.
Help me out.

Tom V.

[mgarblik]

The cam card is a little strange reading over it. But the valve spring info can possibly be explained. Next to valve springs, under, "inner", it says 37/64. Does that possibly mean 90 for the outer plus 37= 127 lbs closed pressure and 262+64 = 316lbs open? That makes more sense considering the grind.

[Tom Vaught]

I THINK YOU ARE RIGHT ON THE TARGET WITH THAT ASSUMPTION, MIKE.

Right in front of my face and did not connect the two sets of numbers.
I lost the rabbit after reading post #5. Think we have it now.

Tom V.

[steve25]

Thanks for trying to educate me Tom, but if you want to get down to brass tacks the cam that was used in the 68 RAII round port motor even thought it’s the same as grind as the 69 and 70 RA4 cam , it was not called the RA4 cam, and his cam card clearly says RA4!

[NeighborsComplaint]

Odd that all the valve timing events were left off the card. They must differ significantly from OEM.

[steve25]

Once agin my point is that if you want the intended rpm range of the that cam in a 400 motor (that can easily and safely buzz to 6400 ) with good surge control even before getting, let’s say to 4800 rpm, then 90 psi on the seat of the Intake valve will not cut it!
Once the springs break in your down by 10 to 12 psi from that 90 psi that already could not cut it!!
I have whitnessed two dyno test , 1 Ford Fe 428 motor, and 1 BB Chrysler 440 where the motors where down not in top end power so much, but in midrange power after the break in session and after just 3 pulls up to 6500rpm.

In both cases the springs where carefully set to 5 to 8 psi more seat pressure then the Cam card called for .
Both motors just in that short amount of run time dropped 10 to 15 psi from the assembled set up pressure and once the heads on both motors got there springs shimmed back up to the seat called for pressure they started at in the beginning of both dyno sessions, all of that mid power dip seen in the Hp graph was gone!

Now mind you the these two motors where not heard to accually be missing when you listened to them in the dyno cell, but it sure showed up in the midrange Torque and HP numbers they made!

This what I am commenting about more then when a Cam was first used or how much I might of been able to buy them for back in 1970!

[Tom Vaught]

Originally Posted by steve25

Thanks for trying to educate me Tom, but if you want to get down to brass tacks the cam that was used in the 68 RAII round port motor even thought it’s the same as grind as the 69 and 70 RA4 cam , it was not called the RA4 cam, and his cam card clearly says RA4!

None of the cams were specifically called the Ram Air II camshaft, or the Ram Air IV camshaft. Or even the 744 camshaft (a Ram Air I camshaft).
The 068 Camshaft was always called the "Tri-Power camshaft" but even that is not totally correct. Wallace has good info on the camshafts.

They went by the Pontiac Part Numbers (last 3 numbers) 068, 744, or 041.
They also had the nose of the camshafts stamped with Letters
Examples being the 744 "H" cam and the 041 "T" cam.

Crane did not stamp the cams in that manner. They added info on the rear of the camshaft.

Crane called the Cams RA-IV because of the basic grind used for that engine.
And the cams many times were "Optimized" with slightly different machining
(advance ground into the keyway for the cam gear on the cam.)

Most cams were close to the same timing but not exact until Crane/Wolverine
and Melling started advertising Blueprint Pontiac camshafts for stock racing classes.

So "I have the Ram Air Camshaft" or I have the "Ram Air IV Camshaft" is just street talk for bragging rights.
Crane went along with that Marketing Scheme for the strokes with the "Ram Air IV" printing.

CMC/ Crane actually offered a High Lift version of the basic Pontiac camshaft grinds.
HO Racing may have been involved in those initial discussions and desires.

Tom V.

ps You make too much out of a camshaft card printed by Crane. That was all advertising.

[i82much]

silly discussion. everybody knows the fastest cars have three-quarter cams in them ...

[steve25]

If you call the discussion of minimum requirements of spring seat pressure silly, then you get the lack of performance out of your motor that you deserve!

The 68 1/2 RAII motor with standard Size D port intake ports (10% smaller then RA4 heads ) and less rpm potential then the RA4 motors still had spring seat pressures of 123 according to my info!

[Tom Vaught]

Originally Posted by i82much

silly discussion. everybody knows the fastest cars have three-quarter cams in them ...

ABSOLUTELY TRUE, i82much, as far as street race cams.
The bad boys are the Full Race Cams.

Tom V.

My 428 engine is 1 cubic inch BIGGER vs your Chevy 427 ZL-1 engine so my engine is better.

Please send all of those "not as good" 427 engines to me

[Steve C.]

Malcolm ''Mac'' McKellar, known best for the camshafts, had a hand in Pontiac's performance history.
After retirement he stated, "I wish we could have used roller technology back then. It would have cut friction and allowed us to improve performance and street manners, but it wasn't available at that time."

Fast forward in time, it would be interesting to ask if he would use those lazy lobes today designing a hydraulic flat tappet cam. I doubt it, and suspect it would go beyond cutting friction !


.

[Steve C.]

Interesting tid bits regarding the 041 cam used in the Ram Air II engine here on pages 80-81......

https://books.google.com/books?id=YU...%20cam&f=false

The No. 041 was often touted in vintage sales literature as the division's first "computer-designed" camshaft. Of that, McKellar says, "That's somewhat true-but not totally. We used a computer to generate the blueprints, and computer technology was hot at that time, so advertising decided to incorporate that.



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