Need confirmation on some 69 GTO specs

[Don_Lightfoot]

I had a very nice 69 GTO for a few years in the mid 1990's. It was the base 400 CI with four speed. Got into a recent discussion with a fellow enthusiast regarding some specs of the 400 CI engines. Unfortunately I can't find all my GTO reference material.

<u>Here is my understanding:</u>
- Although they both had the 350 HP ratings, I believe the base engines had different heads and cam between the four speed and automatic.
- It was also my understanding the cam and heads for the base engine with a four speed were the same as the RA III setup.
- The RA IV setup moved up a step from there.

Carbs and intakes we're not concerned about. Does this guy owe me a beer? Appreciate it.

[442w30]

Hey, there's a forum on this site for Brand X - learn it, know it, live it!


Anyhoo . . . I can't help you here as I've never really kept up with this stuff, but this one stands out:

"t was also my understanding the cam and heads for the base engine with a four speed were the same as the RA III setup."

I don't think that's true. I do know that Pontiac people have been confused with this issue too.

[Don_Lightfoot]

Thanks for the "hand slap" Diego. If the moderators want to move this then go ahead.

[442w30]

I just want to give ya the opportunity for the Brand X whores to see your question - no worries! - but there's always performanceyears.com or classicalpontiac.com.

[StealthBird]

Don, the 69's used either the #16 or #62 heads, while the 69 RAIII, and base 400 GTO (350hp) manual trans used #48 heads. All 3 heads are virtually identical. The #48's are worth more to restorers (especially to the Judge guys) because all Judges were RAIII or RAIV. The #48 heads are much rarer, but offer no performance value over the #16 or #62.

As for cams, the auto trans 69 GTO base engine used the 067 cam, while the 4-speed cars used the slightly more aggressive 068 cam. There's also another cam known as the 744 cam, more aggressive than the 068, that was used on early 1969 Ram Air III cars, then Pontiac switched back to the 068. The 744 cam used more duration than the 068 (same lift), but was a bit too lumpy for everyday use.

The RAIV was a different animal entirely.

[442w30]

I should have known to give you a heads-up, Mike!

Now, to throw Don's head into a tizzy, weren't the 1970 heads different?

[Don_Lightfoot]

Thanks very much Mike, appreciate it.

I finally found some of my resource material which confirms what you said:

Base 400/350 Auto - Heads 9790118 #16, Cam 9779067-P.
Base 400/350 Manual - Heads 9795043 #48, Cam 9779068-S.
Ram Air III - Heads 9795043 #48, Cam 9785744-H (up to engine serial number 709185) then 9779068-S.

Think I will ask for a Labatt's Blue

[StealthBird]

The 1970 heads were again changed from 1969, using slightly lower compression. The 1970 base 400's used the 067 cam regardless of trans, and the 1970 RAIII's received the 068 cam regardless of trans.

Now how about these WILD Pontiac 067 cam specs for the GTO.

A whopping .406 lift int/exh (break out the lifter bore braces guys)
A staggering 273/289 adv. duration.

It's amazing that base GTO's ran as well as they did. That earlier cam we mentioned (known as the 744) that was used in early RAIII 1969 GTO's was also used (with a different distributor gear) in the 73/74 SD-455's. Still nothing to write home about. Again, .406 lift, but a little longer duration at 301/313.

Pontiac utilized low lift flow to fill the cylinders in order to make power across a broad rpm range. That's why most Pontiacs were all done by 5200 rpm.