# 067 or 068 cam on stock Gto?



## RMTZ67 (Mar 12, 2011)

Gonna rebuild my 1967 Gto back to stock. But I was wondering what the pros and cons of a 068 over a 067 cam? Would the 068 raise my already high compression motor even more? I was planning on new springs either way. and would the push rods be the same? What if any can you tell me about aviation fuel for these cars?


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## My65goat (Jul 26, 2017)

My car has the 068 in a 389 with the tri power. It was rebuilt with stock style pistons and has probably close to the original compression. I'm guessing it is probably 10.5 and I have no problems with 93 octane. The one thing that I like to do is mix a little 110 octane with the 93. To me it is just a little insurance plus is smells great out the exhaust. 
I go to the local dirt track and pick up five gallons at a time. I mix 1 gallon of 110 with 4 gallons of 93. For the dozen or more times a year I take the car out it that 5 gallons lasts all year. I am even thinking about mixing it 1 to 5 this year.


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## Bob Young (May 27, 2018)

I have the 068 cam in my car stock with 10:75. Properly tuned and a mix of 100LL it does fine. Have a spare cam should I ever need it, sorry not for sale.


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## geeteeohguy (Feb 2, 2008)

The 068 will be BETTER with today's gas than a tighter 067 or even tighter 066. Less cylinder pressure. I've run one in my '67 GTO since 1988 when I overhauled it. That was 90,000 mile ago. Works great, but in CA where I am, I can only get 91 octane fuel, so I yanked the heads and installed 87cc 1970 #15 heads for a CR of about 9.3:1. 068 was a great cam for these engines then, and still is. Go for it!


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## RMTZ67 (Mar 12, 2011)

geeteeohguy said:


> The 068 will be BETTER with today's gas than a tighter 067 or even tighter 066. Less cylinder pressure. I've run one in my '67 GTO since 1988 when I overhauled it. That was 90,000 mile ago. Works great, but in CA where I am, I can only get 91 octane fuel, so I yanked the heads and installed 87cc 1970 #15 heads for a CR of about 9.3:1. 068 was a great cam for these engines then, and still is. Go for it!





My65goat said:


> My car has the 068 in a 389 with the tri power. It was rebuilt with stock style pistons and has probably close to the original compression. I'm guessing it is probably 10.5 and I have no problems with 93 octane. The one thing that I like to do is mix a little 110 octane with the 93. To me it is just a little insurance plus is smells great out the exhaust.
> I go to the local dirt track and pick up five gallons at a time. I mix 1 gallon of 110 with 4 gallons of 93. For the dozen or more times a year I take the car out it that 5 gallons lasts all year. I am even thinking about mixing it 1 to 5 this year.


just what I was hoping to hear. Did some research and that was the conclusion I came up with. But seemed to good to be true. I as well am on the tipping point with 93 octane so I will do a little mixology as well. I tried a multi quote to respond to all. Is that how a multi quote works? But it gave me a error page.


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## RMTZ67 (Mar 12, 2011)

*O68 Mistress*



Bob Young said:


> I have the 068 cam in my car stock with 10:75. Properly tuned and a mix of 100LL it does fine. Have a spare cam should I ever need it, sorry not for sale.


some how left you out of the multi quote. I have already been on ebay searching for such a fine piece of GM history. No such luck as of yet That piece there would sleep between my wife an I. Well maybe I exaggerating just a little bit. Thanks for your input.


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## 70sportstripe (Jun 22, 2018)

068 here.

Just enough lope to sound good, enough vacuum to keep everything
working properly.

93 octane no ping.

My engine builder said he had the cam custom ground to 068 specs.


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## geeteeohguy (Feb 2, 2008)

Melling SP-7, I believe


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## RMTZ67 (Mar 12, 2011)

Will my current stock 067 pushrods,rockers and springs work with this 068 cam? I will be buying them new.


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## PontiacJim (Dec 29, 2012)

RMTZ67 said:


> Will my current stock 067 pushrods,rockers and springs work with this 068 cam? I will be buying them new.


Yes. Pontiac for the most part kept lift the same - .406" lift. What they did was to increase duration & overlap to make the cam's "bigger." However, aftermarket cams will increase lift on their cams and play around with the Lobe Separation Angles in an attempt to "improve" the cams. So be aware of this and get a cam spec'd as original or you may get into trouble with stock parts and/or stock compression.

Make sure when you get new lifters that they are the correct "Pontiac" style and not the sometimes mis-used Chevy type which will fit the lifter bore, but not work. Pontiac has a specific band height around the lifter body. The Butler website has a comparison in their tech section.

Summit sells one: https://www.summitracing.com/parts/mel-spc-7/applications


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## Bob Young (May 27, 2018)

If you are wondering how lumpy a 068 cam is, here's one at idle. Couldn't post a video here but...I'll try it this way. I'm not too advanced in the video posting stuff


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## Vance Morgan (Jun 24, 2018)

Didn't know about the specific Pontiac lifters. I got mine from now defunct Indian Adventures. The "068" cam is on a 116 lobe separation angle (LSA). I run the Summit 2801 cam with a little more lift on a 112 LSA.


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## RMTZ67 (Mar 12, 2011)

So since the engine had been rebuilt in the past. I was wondering if my rockers and springs have been changed already? are they stock or aftermarket? anybody have a pic of a original any clues if the springs have been replaced ? What brand/type valve guides and seals are the best?


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## tmd171 (Oct 8, 2017)

Hey Bob, I listened to the video and really like the sound of your Pontiac! What muffler and pipes are you running?

Thanks, Tom


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## Rick Hipp (Nov 18, 2021)

My65goat said:


> My car has the 068 in a 389 with the tri power. It was rebuilt with stock style pistons and has probably close to the original compression. I'm guessing it is probably 10.5 and I have no problems with 93 octane. The one thing that I like to do is mix a little 110 octane with the 93. To me it is just a little insurance plus is smells great out the exhaust.
> I go to the local dirt track and pick up five gallons at a time. I mix 1 gallon of 110 with 4 gallons of 93. For the dozen or more times a year I take the car out it that 5 gallons lasts all year. I am even thinking about mixing it 1 to 5 this year.


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## Rick Hipp (Nov 18, 2021)

I discovered while taking a fuels and lubes class that aviation fuel while having higher octane, actually makes less power than gasoline. Good to know.


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## BearGFR (Aug 25, 2008)

Rick Hipp said:


> I discovered while taking a fuels and lubes class that aviation fuel while having higher octane, actually makes less power than gasoline. Good to know.


Because octane _rating_ has >absolutely nothing to do< with making power. Zero. Zilch. Nada. Octane _rating_ is a measurement of a fuel's ability to resist detonation and nothing more - that's it.



> My car has the 068 in a 389 with the tri power. It was rebuilt with stock style pistons and has probably close to the original compression. I'm guessing it is probably 10.5 ...


Maybe, if your heads are the originals and actually have 65 cc chambers. The published compression ratios from the factory were applicable only to engines that exactly matched the _factory blueprint specs_, which almost none that rolled off the assembly line did, and Pontiac head chamber volumes are known to vary somewhat from the published specs. I recently posted about this on another thread. Some sites claim that the actual compression ratio on stock 65 389's with 65 cc chambers was as low as 10.26:1 It doesn't take much in the way of chamber volume to have a big effect on compression ratio. For example, moving up to 72 cc's from 65, like if you happened to be running later model open chamber D-port heads, that 7 cc difference would drop it to just over 9.8:1.


Bear


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## bigD (Jul 21, 2016)

For you guys mixing fuel to increase octane: Have ya'll tried using a GOOD octane booster, such as Torco Accelerator ?

Should be much less hassle. Might be cheaper, too. With a quick price check, Amazon had the lowest I found. 









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Torco Accelerator Bottle 32oz


Torco Accelerator Bottle 32oz - not just another octane booster, it's a race fuel concentrate race gas fuel additive. It boosts pump gas octane up to 14 points.




torcoracefuel.net


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## integrity6987 (May 10, 2017)

bigD said:


> For you guys mixing fuel to increase octane: Have ya'll tried using a GOOD octane booster, such as Torco Accelerator ?
> 
> Should be much less hassle. Might be cheaper, too. With a quick price check, Amazon had the lowest I found.
> 
> ...


I use this b/c without it (or CAM2 race fuel) it pings under load. It works well.


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