Has anyone here ran the Duntov 3030?

That was the base gasket. I just left it in place when I shot the photo.

 

I guess my intent is that people are just spouting out shit they did 40 years ago and others are spouting out what their computer says different cams will do... while Simeon's out racing a bitchen '55 Chevy with a Duntov 30/30 327... and hauling ass.

It's like arm chair quarter backing until you post pictures or video of what you're currently doing.

We're still gonna try the Tarantula and the 850...

Sam

 

Ever try running it with a smaller carb???...

 

To go back to the original posters question about various cam timings;

 

You'll be joining a large, and not very exclusive club, McGurk. Every time I open a cam or carb thread on the HAMB, I hear banjos playing. By now, I should know better, I have no excuse. Later I'll send you a pm later about the carb mods.

 

I disagree. I'd hardly compare "armchair quarterbacking" to anyone who's run this cam, even if it was 40 yrs. ago. Unless the person is senile; why would the info be bad or wrong just because it was 40 yrs. old? The SBC didn't change in that time frame, so the info is still good.
Funny that people need pictures or videos these days to believe or understand car talk.

 

This is my 331 with 30 30 cam just got it fired this weekend. Ron http://www.youtube.com/watch?v=e4yq70UswtQ

 

I've run 30/30's, not in my own stuff (I had more sense) but in stuff I built for guys that couldn't understand a cam card (thats traditional) and just wanted to make noise. When I was at Dix in the seventies, I could buy a TRW 30/30 for about $35 wholesale, and there were lots of guys I did motors for that wouldn't pony up the bucks for a real camshaft. dont worry, there wont be any more tech advice from me, just setting the record straight.

 

Oh, and nothings changed, they were a dog in 1975, and they are dogs now...

 

I like this shot. What will it be going into?

 

Thanks it for a 55 210 sedan. But going back together as a 150 utility sedan. Ron. http://www.youtube.com/watch?v=e4yq70UswtQ

 

Nice '55. It shall have the idle and wind of yesteryear. When your out driving many 55 (pun) yrs old and up guys feel nostalgic and maybe, for brief moment young again. Carry on.

 

That's for sure my first solid lifter cam had a notch in the rear journal for oiling the old 265. That was around 67. This method for adjusting these old cams works well. If you don't like doing it running and throwing the clips off. Ron
http://65corvette.nonethewiser.net/technical/VlvAdjArticle.pdf

 

I'm just saying... there are those that do, and those that did... and very few that did and still do.

Sam

 

I had used the 30-30 in three motors. Great cam, exceptional power curve, nice lumpy idle, but had some noise clatter though. Still have a new unused one left in my goodie box.
Might use it on a 327 for one of my hopefully future projects.

 

I'd agree with that! When I built my 327 for the Austin in my avatar I never considered the 30-30, even though Comp Cams still sells a clone. I went with the Isky 270, which I felt was a better choice for my combo.
And I also agree that there are numerous cams on the market today that are better choices for the street or the strip, and each engine build should be assessed for all components before choosing a certain cam.
But putting a full sized '55 Chevy into the low 12's with a 283 and a Duntov 30-30 told me that it is definitely not "horrible things", as described in the Buddy Morrison article. I can remember well my first ride in my buddy's new Z28 when I was home on leave, and it was one of the most impressive factory stock cars I'd ridden in back then!

 

There was a good point that was almost brought up on carb size. The pic of the carb boosters posted earlier showed a step machined into the bottom of the booster. This helps shear the gas droplets which helps big carburetors work better at low airflow.



Now I went back and read the first post and it was 2 years ago so we are way off on our own. There are just so many variables when you are putting together a combination. The simulations assume you have tuned the combination to the max. Probably more in the carb than the cam on that 327 anyways.

 

Maybe it's not what you know, but how you share eh? I have learned lots here, not so much on the last tenth in a cam like when we ran with Hamm, Rehr, Cross, Shepherd , Brown ,Morrison and all the other 70s Div 4 cats...but on some cool ideas. I haven't run a 57 chevy or a 30-30 since 69 or so, but both are still cool

 

falcongeorge,

We're like young studs in a lesbian den. I tried to flip a couple them back in the 60s and they didn't want to hear about let alone try it. They were content with using toys and strap on devices.

These guys are not interested in what we have to say or they would have taken the time to read a few of the numerous camshaft articles that explain the various aspects of camshaft timing and the effect they have on an engine.

Give up!

If there are readers that are interested then consider the following information:

1) Blown gas engines typically run camshafts with a 110º to 112º LSA.

2) The camshaft in my blown alcohol 364ci SBC had a 114º LSA.

3) The GM 30/30 camshaft has a 112º LSA. Limit your respiratory activity to once every fifteen seconds while running as hard as you can run. I will guarantee you that you will not reach your maximum potential. That's what you are making your engine do. Your engine has no choice so it makes the best of it. As I stated in a previous post: When you compromise camshaft timing in order to facilitate a vacuum brake booster then it cannot be that great of a camshaft.

If the GM 30/30 camshaft had a proportional amount of lift and duration then it would be right at home under a blower, but if maximum performance is your quest then it's misplaced under a carburetor. However taking full advantage of the engines pumping displacement can lessen the adverse effect of the wide LSA.

I worked at a Chevrolet dealership when the 30/30 camshaft was in production. The C2 Corvette hood would not allow for a high rise intake manifold so Chevrolet made another compromise and used a low profile intake manifold with a Holley List 2818-1 carburetor that was rated at 580 CFM. The low intake velocity necessitated using the small carburetor.

One of the salesman had a 1965 Corvette with a 365 HP 327, headers, 4 speed and 4.11:1 posi. He ask me what he could do to improve the performance. I told him that I would replace the low profile intake manifold with a Z28 high rise intake manifold and Holley List 4053 carburetor rated at 750 CFM. There was a Z28 in for warranty work and waiting for a short block. The intake manifold and carburetor were setting under my bench. I don't recall the specifics, but the swap made a substantial improvement in the ET and MPH. The Holley List 3310 rated at 780 CFM would have probably gained more, but it was never tried. That is how we learned back then and it's a time tested method that is still used by many today.

John ordered a new hood and had the body shop graft a hideous medieval looking blister on it. The Camaro left with a new short block, intake manifold and carburetor. As I recall there was a problem with his carburetor so it had to warrantied.

If you want to use a 30/30 camshaft then I would suggest using the Comp Cams part number #12-673-4.

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=232&sb=2

The modern lobe profiles require .012" valve lash. You will still have some clickity click, but you will not have the impact hammer effect of the GM 30/30 camshaft. That camshaft was the absolute worst when it came to pulling the pressed in rocker arm studs out of the cylinder heads.

falcongeorge and myself view thing from a different perspective than people that are interested in building period correct hot rods. We both mean well, but we mistook your interest.

McGurk

 

Actually, i am all abot period correct hot rods. I just beieve in using the best parts the period your building for has to offer. But yea, we definately come at it from a different perspective.

 

The bottom line has always been known, these ancient cams compromise a lot of power when even compared to 80's technological advances. McGurk, your logic, delivery and patience is far more palatable in every regard. Thank you.

 

Oh, forgot to add that indeed in my bio I make no bones (Bare Bones) about the modern Lunati cam in my 'put-put' boat anchor (some members fondly called it that). It can be daily driven if need be. Perhaps the next older ('55 w/ major wheel well radius, tilt ft end ect) will be a far more potent and very limited driving range ride. These old cams do inflect the ire of the techie side of the male ego at times. Keep it civil, and teach/learn is all a person can ask for.

 

Since LSA keeps coming up, ans understanding that there is never just one answer, here is the Vizard LSA Chart. A 327 with a 1.94 intake valve would be a 108.8.

 

Gross oversimplification. I've seen this chart before, in its original context, and I get what Vizard is trying to do here, but intake port flow/velocity (which is only vaguely related to valve size) relative to displacement is just one of a long list of factors that can influence LSA selection.

 

I think most learning discussions would start from the simplest example and expand...

 

Yes,but there are engines with huge intake valves and very limited performance like the 2 inch intakes in the 134 Willys F head and the Chevy 235.
You have to consider the whole package and it's likely what Vizard is getting to. So a chart taken out of context is meaningless .
Of course I may be full of shit as usual

 

My intent was for a discussion starter. Why does the chart imply that the smaller the valve area per cubic inch the closer the LSA. ? What are the limitations of this generic chart.

What does changing LSA generally do?



And there would be more discussion about that.

Eventually we would get to overlap, velocities, cylinder dwell, and the fact LSA is only one factor amongst many .....and we all learn without any alluding to one's back river banjo experience...oh well what was I thinking the eternal optimist

 

Maybe I should have said the chart is more meaningful when included with the other variables.

 

From David Vizard;

"How Do You Know What LCA Is Needed?
Now we come to what would normally be a real stumbling block. Exactly what LCA does an engine need for optimal results? The bottom line is that it's all related to how big a cylinder the intake valve has to feed. The bigger the cylinder in relation to the valve, the tighter the LCA needs to be, and vice versa. That is the main factor. Additionally, but to a lesser extent, we also find that as the compression ratio goes up, the optimal LCA gets wider. This is good because it means smaller valve cutouts in the pistons. For an engine in the 9 to 11:1 CR range, the LCA selection chart will, 99 times out of 100, deliver accurate results. For each ratio above 11:1, it pays to spread the LCA about 1 degree for every two ratios of compression increase. "