Anybody running the '68 4 speed 340 cam?
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AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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That is gunna be highly dependent on several things, such as 1) actual cylinder pressure and ring-seal
2) actual ignition-timing,
3) actual valve lash
4 internal engine friction
5) the running temperature
6) local conditions, including elevation.
7) the rear gear, car weight, aero, chassis drag.
To me, the numbers you asked for are irrelevant. but I would expect them to be quite low, somewhere around 10, maybe a bit less @700idle, and 18@2400, if she's getting the timing she wants which could be around 50 or more degrees.
Mine likes a minimum 56*
276/286/110@008 advertised, and 230/237@050.
2) actual ignition-timing,
3) actual valve lash
4 internal engine friction
5) the running temperature
6) local conditions, including elevation.
7) the rear gear, car weight, aero, chassis drag.
To me, the numbers you asked for are irrelevant. but I would expect them to be quite low, somewhere around 10, maybe a bit less @700idle, and 18@2400, if she's getting the timing she wants which could be around 50 or more degrees.
Mine likes a minimum 56*
276/286/110@008 advertised, and 230/237@050.
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Thank GOD we're not all you.
@krazykuda made that happen I believe. He should know but he isn't on all that much lately.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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And thank God yur the only one like you on this forum. It's guys like you who drive newbe's away. You can never just state your case, without plastering yur poop-stamp on it.
ME? Pot, kettle, black. All that. LOL
I’d dispute some of those variables like #7. It’s a new stock 340 with Eddy intake and carb. I’ve changed some of variables with little change to intake vacuum unless I crank initial timing up well above 18 degrees. All I want to know is the normal range. One member had heard that it was low with this cam and maybe not suitable for power brakes (which i don’t have).
I would simply ignore his post. He's another dantheman. Giving advice when he doesn't even have a Mopar anymore.
12 degress (BTDC) Before Top Dead Center is the factory stock setting with Mopar electronic ignition and brain box.
If you are running the Mopar HEI conversion and hotter faster E-core coil, then you need to back it down to 8 degress BTDC, and gap the plugs at .050 ths.
Stock Build 340 with the 4 speed 340 cam.
* * * * *
If you are running the Mopar HEI conversion and hotter faster E-core coil, then you need to back it down to 8 degress BTDC, and gap the plugs at .050 ths.
Stock Build 340 with the 4 speed 340 cam.
* * * * *
I never knew anything came "factory stock" with electronic ignition in 1968. Do tell.
i've repeatedly asked @George Jets for any evidence of this "hotter, faster" magic coil and he has yet to post one shred of literature or any facts to back up this suspicious claim. so i'd chalk up that whole "back the timing up for HEI" as piss poor hot rod folk lore.
also we don't need 50 gaps that eat up ignition components. our cylinders are very efficient, it's not like we have pontaics and are trying to eek out 35mpg.
anyway, i just did up a 318 with a 340 4spd cam (advanced 4°) that i was running a e-burg mopar electronic set up and it was delighted with 14°
ultimately, the motor will want what it will want and it'll let you know.
I was thinkin maybe he skimmed over it was the 4 speed cam we were talkin about here. ONE year only, 1968. We all know there was no electronic ignition "then", so there was no stock spec for timing for "that" package, since it never existed. Maybe he thought the two cams were the same.
that's understandable, it's kind of a unknown entity... howevah! to suggest below 10°? that's madness.
bet it cranks over like a mutha and you can get on it without ever worrying about detonation.
340six
King Of Bling
I hope Amazon has hip boots on sale. I need some for the deep BS at this point. All threads get deep here. Carry On.
So less initial timing will give it more vacuum at idle ?
search.brave.com
Good for answers > can answer with artificial intelligence AI search.
☆☆☆☆☆
really? it's come to this? a ******* copy pasta of some AI bullshit?
wow. this is some clown shoes action over here. great job there george. top marks all around.
AI will trash can plenty of items with horrible advice/truths!
I've seen some whoppers with those AI answers. Including people still alive who have been dead decades and the reverse. lol
mygasser
Well-Known Member
agreed, the wife read online yesterday that our (relatively) new king Charles had died which was of course bollocks
neil.
AJ/FormS
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You don't knowchit about me and my Mopes.
The #7 above speaks to cruising it.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I ran power brakes with a 292/292/108 cam in, straight-up. also at +4, and +8. I had no problems with my booster, other than backing out of my carport, in the morning.
Since then, I have been thru two other cams, a 270/276/110, and the current one is a 276/286/110.
None of these have a shortage of vacuum; not at idle and not at cruise.
Boosters have a large storage chamber, that when it is evacuated, it will give you at least one panic stop from 65 mph, even if you turn the engine off.
So to evacuate the booster, mine, cold, only takes a couple of blips of the throttle, which I do anyway while backing out f my carport to keep it running, cuz she has no choke and my Idle timing is just 12 to 14....... cuz you know, I like to drive slow. which is really hard to do with 20 degrees. Sometimes I crank it back to just 5 degrees to drive just 4mph. Imagine my engine vacuum. Don't ask me what is, cuz I don't care, that's why the booster has a checkvalve built into it.
Of course on the hiway, in overdrive, at 65=2240, with 51 or so degrees advance, there is plenty of vacuum, and since mine is a manual trans, downshifting keeps the vacuum up, all the way to a stop.
Surely your 340 cam will make more vacuum than mine.
Surely somebody fed you a line.
Surely you will never run a 292 cam, lol.
But, IMO, surely; don't try to run that little Duster dual-diaphragm, it requires too much vacuum to start charging it.
I run some big "monster" off a 73 Dart that starts charging at something like 8 inches. Plus, I have retimed mine now, for less boost, cuz passengers don't like their noses plastered into the dashpad.
Oh and with a 4-speed, behind my 11.1/1 engine, when I lift off the gas, it's like a regular automatic applying the brakes pretty hard, as it is. Engine-braking is a wonderful thing.
Oh and, I don't run any proportioning on my rear brakes, cuz there's 295s back there. So then, when I do brake, it's like instantly towing a rock-laden sled.
My booster/and brakes have been recalibrated to work the way I want them too. She wears out the rear shoes pretty often, whereas the front pads now have over 135,000 miles on them.
Engine-braking together with full-pressure rear brakes are awesome. Ask me if I care about how much vacuum my engine makes at idle or while cruizing; I just don't ever think about it, cuz it's just never been an issue. Well, not quite true; that dual diaphragm was no friend of the 292 cam. At the first, I bought a hill holder, so I could put the trans in neutral at a long light, so that the booster remained charged.
But, in the end I found this nice old booster in my junkpile, and surprise, it still worked.
As I mentioned I am not running power brakes. Idle vacuum of 10-12 and 15 during cruise seems low on a new engine. I was curious as to what others were getting and whether I should look deeper than I have done already for a vacuum leak.
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