340 cam specs?

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Krooser said:
Do you remember Comps original name?

I visited their operation on Democrat Rd in Memphis a few times in their early years....looked like a few Berco grinders and some other older machine tools. Advertising has done a lot for them.
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Before Competition Cams?
I will say this. When I was shopping for a cam a few years back, I was calling them every week or so. And got a different recommendation from every cam "tech." Next time it will be a call to Racer Brown probably, and just have a cam ground for my engine.
 
A few of the guys worked for other cam companies (Cam Dynamics comes to mind)
 
First engine I bought came from RHS. Toward the end of when they did that sort of stuff. 1989-90 IIRC. Still have a catalog or two.
 
a well know quote was
To be a successful cam company never open the dyno door
I remember when Edelbrock first showed dyno reports on the 383 and 440 manifolds
Turned out that they only had one motor and "dry labed" the other
I forget which
you sell what you tell even if it's BS
 
fratzog lover said:
Before Competition Cams?
I will say this. When I was shopping for a cam a few years back, I was calling them every week or so. And got a different recommendation from every cam "tech." Next time it will be a call to Racer Brown probably, and just have a cam ground for my engine.
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that happened to me as well, in 2004, from a different company. I went back and did some learning, took a chance on a Hughes and am sorta satisfied; but if I ever buy another cam, it will be a solid FT.
 
krazykuda said:
Ok we were discussing the 340 4 speed cam in the coffee thread and it was suggested that I post my info here...

I bought a set of custom ground 340 cams from a member here many years ago and have been saving them on the shelf... Another member asked if I would mind sending them to Oregon Cams so he could have one made, so we sent my cams to Oregon Cams and Ken Hoard measured them...

He can now make one of the 340 4 speed cams off of the "layout" that he did on mine... One of the lobes was a couple degrees off, but he can bump it to get right on the spec... The only area mine was off, was the exhaust lift was .006" less than the factory spec...

Here's the layout from Ken Hoard of the stock 340 Automatic cam that was custom ground to the specs:

View attachment 1715410901


Here's the layout from Ken Hoard of the stock 340 4 speed cam that was custom ground to the specs:

View attachment 1715410902


Here's my degree info compared to the Ken Hoard data:

View attachment 1715410909

View attachment 1715410910

Ken Hoard is able to bump the one lobe that is off to the proper location to match the 340 4 speed cam specs from the service manual if anyone is interested in one, contact him at Oregon Cams and he can make them now... This may be the closest to getting the 340 4 speed grind so far...
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Sorry I haven't had time to think about this.

You guys will have to help explain all the pencil notations.
But here's my first take away.
OCG shows the duration at .006 tappet as close to the FSM.
SAE is 0.004 at the lifter, and dynomation calculates based on .006 at the valve.
OCG didn't measure at .004, but we can see the .004 will be between the .002 and the .006 durations. So that confirms what we were saying earlier.
 
OCG shows the duration at .006 tappet as close to the FSM - not close
FSM is more like.008 at the cam like Engle
SAE is .006 at the valve which is .004 only with a 1.5 rocker
.004 will be somewhere between the .002 and OCG gives but hard to say where
factory cams get longer the lower the measurement
340 cam is like a 280 class crane or cam dynamics or Summit, sealed power, elgin etc .004
or a 270+ comp lunati or other .006 cam

340 68 auto and 360HP cam
279/289 @.004 429/444 114LCA
268/276 @.008
 
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Bumping this back up as it had some helpful information for me. Here is my cam card I got with the car so it looks like the cam is essentially a "stock" 340 cam. It's an Erson cam I couldn't find on their website.

IMG_0682.jpg
 
1971 CY Dodge Dart said:
Bumping this back up as it had some helpful information for me. Here is my cam card I got with the car so it looks like the cam is essentially a "stock" 340 cam. It's an Erson cam I couldn't find on their website.

View attachment 1715637710
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Thanks for sharing the Erson card.
Interesting that it says the opening and closing degrees are at 0.005" lift
Maybe Wyrmrider, TMM or one of the orther guys has some insight into Erson's specs.
My guess is Erson had the cam ground by another company (one of those big cam companies Wyrm has mentioned) and then Erson just filled in the cam card using the Chrysler shop manual specs. They might not have even realized the open and closings were not measured from lifts. For the .050 I don't know but probably are the numbers they got from the grinder.
 
All I have to say is the OEM's and aftermarket sure screwed things up by not having a industry standard for cam specs.
 
I actually question if that Erson cam is still in my car. One of the previous owners that I spoke to had the motor built with that cam. He said the car never loped like it does now. The only changes made after him were the mufflers I believe. I’m still trying to piece everything together as far as the car is concerned and what I have. I thought I had 3.91 gears but I actually have 3.23’s.
 
fratzog lover said:
.429/.444?
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Pretty much. The 68 4 speed cam had the smaller cam exh lobe as intake 276-445, and put the 440 284-458 cam intake lobe on the exhaust side, IIRC.

Plenty of info that is not correct and been printed in books for years.
 
65, the two Pontiac cam specs they provided are reversed. The 041 is the larger of the two. :):)
 
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