Thread: ram air what??
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Old 04-23-2026, 12:49 PM
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unruhjonny unruhjonny is offline
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Quote:
Originally Posted by 73T/A View Post
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.

__________________
1970 Formula 400
Carousel Red paint on Black standard interior
A no-engine, no-transmission, no-wheel option car.
Quite likely one of few '70 Muncie three speed Formula 400's left.


1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing)
2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs)