Replacement 68 340 four speed cams

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My 99.9% stock 340's would run 14 flat go 165 and get about 20 mpg on snow tires with no posi. no o.d. Stock exhaust system. I have plenty of witnesses. There may be some better stuff out there but it always worked for me. Now add 1.6 rockers, 11.0 to 1, o.d. 4.10's headers etc. what would you get today. Add a high-pressure fuel system. Wow just imagine what you'd get out of that little 340 with a 55 year old cam. O, with 55 year old heads to boot. Now ...
 
My 99.9% stock 340's would run 14 flat go 165 and get about 20 mpg on snow tires with no posi. no o.d. Stock exhaust system. I have plenty of witnesses. There may be some better stuff out there but it always worked for me. Now add 1.6 rockers, 11.0 to 1, o.d. 4.10's headers etc. what would you get today. Add a high-pressure fuel system. Wow just imagine what you'd get out of that little 340 with a 55 year old cam. O, with 55 year old heads to boot. Now ...
165 mph in the quarter mile?
 
I would assume that the 52 degrees overlap is based on 0.006 lift and not 0.050 just like their duration numbers (or whatever low lift number they used). My Oregon cam card shows 42 degrees overlap.
Right. All the Chrysler stuff was given advertised.
 
My 99.9% stock 340's would run 14 flat go 165 and get about 20 mpg on snow tires with no posi. no o.d. Stock exhaust system. I have plenty of witnesses. There may be some better stuff out there but it always worked for me. Now add 1.6 rockers, 11.0 to 1, o.d. 4.10's headers etc. what would you get today. Add a high-pressure fuel system. Wow just imagine what you'd get out of that little 340 with a 55 year old cam. O, with 55 year old heads to boot. Now ...
I like my "OLD" simple stuff. I hear people spending thousands to gain .20 in the quarter. I don't get it, when the consistently maters. Chrysler did it right, with DC help.
 
My 99.9% stock 340's would run 14 flat go 165 and get about 20 mpg on snow tires with no posi. no o.d. Stock exhaust system. I have plenty of witnesses. There may be some better stuff out there but it always worked for me. Now add 1.6 rockers, 11.0 to 1, o.d. 4.10's headers etc. what would you get today. Add a high-pressure fuel system. Wow just imagine what you'd get out of that little 340 with a 55 year old cam. O, with 55 year old heads to boot. Now ...
what was the .1% that wasn't stock?
 
I for one can vouch for the 340s top end charge. My 73 340 Rally Charger with 78K on the clock hauled me and five friends out to the junkyard one Saturday in 1981. One of the guys in the back, Jeff Clark said "hay Rob, will it bury the 150 speedometer?" I said "I don't know, I ain't tried it yet." Then I firmly planted my foot on the floor and just held there. I had the needle pointing a little past straight down before I lifted. 150 was about at the 5 o'clock mark. The car was all original with the original 73 supposedly "lower" performance 340, stock manifolds and stock exhaust right down to the original mufflers and slotted exhaust tips. I routinely outran a school friend's 70 396/375 Chevelle. Pissed him off so bad every time he demanded a rematch. I remember only once when he got me and it was by a bumper. We all knew that car was faster and quicker than it "should" have been....and it was. It had to be all over 4000 pounds that Saturday with six of us in it. I think their curb weight is a tick under 4000. 3850 or some such? Here's the car. The guy I got it from got drunk in it not once, but twice. Hit a brick mailbox the first time and a brick wall the second time. His dad took the car from him and that's when I paid 300 bucks for the car. We found good fenders, bumper and grill for it in a local junkyard. That's why the fenders are brown. You can see the damage on the hood. That car would slap move for a big car.
ME & CHARGER.jpg
 
i agree.

pretty much everyone grinds it as the AT lift, but with the MT duration and on a 114
(which i think is butt, let the record reflect)

now gimme that factory cam on a 110 and we talkin' it's brie time baby.
Yep,
For what its worth, Schneider ground me a 264/274 .445/.450 222/230@ .050 110 lsa solid for my sons 72 340 auto Dart with 587 1.88's. power brakes and oem exhaust.
 
That's a different grind than the 4 speed cam. The 4 speed cam was a dual pattern, just like the auto cam. It had more duration though and it may have had more lift too.

Yeah, here it is from @krazykuda right out of the 1968 service manual.
68 340 4 speed cam:

276°/284° duration
.444"/.453" lift

Int open: 26° BTDC
Int close: 70° ABDC
Exh open: 78° BBDC
Exh close: 26° ATDC

Overlap: 52°

Per the 68 factory service manual


here's the spec straight from the DC catalog page

P3412044 68 340 Man.-114 276/284 .444/.453" 112

P3690213 Street Hemi GT-112 284 .471/.474" 109

auto 340: 430/444 268/276
manual 340 (68 only): 444/453 276/284

comp *used* to make a very similar cam to the manual 340 unit. i'll root around in my notes to see what i can find.

most all the aftermarket makes a version of the standard 340/360 4bbl cam. i like the melling piece personally.


Here's the specs on most of the factory stock camshafts for a SB....

1736433852510.png


I made a spreadsheet of camshaft specs and did calculations forward and backward to check if the specs were correct... I did find a few with some conflicts and was able to correct most of them from doing the math forward and back and checking with the listed specs for the cams...
 
here's the spec straight from the DC catalog page

P3412044 68 340 Man.-114 276/284 .444/.453" 112

P3690213 Street Hemi GT-112 284 .471/.474" 109

auto 340: 430/444 268/276
manual 340 (68 only): 444/453 276/284

comp *used* to make a very similar cam to the manual 340 unit. i'll root around in my notes to see what i can find.

most all the aftermarket makes a version of the standard 340/360 4bbl cam. i like the melling piece personally.


Do you have the old DC catalog(s)???

Would you mind sending me a copy or pictures of all of the camshaft spec pages for all of the engines and from which catalog (year) that they are from??? Slant 6, SB, BB, & Hemi.... I would love to add them to my spreadsheet... I only have the Mopar Performance catalogs to use for specs, but would love to get the info on the old DC catalogs...
 
That's a different grind than the 4 speed cam. The 4 speed cam was a dual pattern, just like the auto cam. It had more duration though and it may have had more lift too.

Yeah, here it is from @krazykuda right out of the 1968 service manual.
68 340 4 speed cam:

276°/284° duration
.444"/.453" lift

Int open: 26° BTDC
Int close: 70° ABDC
Exh open: 78° BBDC
Exh close: 26° ATDC

Overlap: 52°

Per the 68 factory service manual

here's the spec straight from the DC catalog page

P3412044 68 340 Man.-114 276/284 .444/.453" 112

P3690213 Street Hemi GT-112 284 .471/.474" 109

auto 340: 430/444 268/276
manual 340 (68 only): 444/453 276/284

comp *used* to make a very similar cam to the manual 340 unit. i'll root around in my notes to see what i can find.

most all the aftermarket makes a version of the standard 340/360 4bbl cam. i like the melling piece personally.


Lets see if this is more readable... (For us old guys with 'old eyes'...)

1736434538048.png



1736434379406.png



1736434431224.png


1736434288939.png
 
Rusty, its stories like the one about your 73 Charger and your write up RRR guide to hot rod bliss that got me interested in building a simple 340 combination.
Im 56 so i missed these cars when they were new so i want to experience the "legendary 340 " in 1968 specs... engine builder is machining the block now and estimates early spring, hes also going to break it in on the dyno, i"ll share the results....
 
I would assume that the 52 degrees overlap is based on 0.006 lift and not 0.050 just like their duration numbers (or whatever low lift number they used). My Oregon cam card shows 42 degrees overlap.

No, the 52° overlap is based on the seat-to-seat duration numbers and matches with the lobe separation and duration figures as you can see in my charts that I posted above... I used data straight from the factory service manuals for my spreadsheets...
 
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Seeing it’s in the machine shop make sure to get at least 10.5 to 1 minimum I really like 11 but I’m not afraid of mixing my fuel.
 
No, the 52° overlap is based on the seat-to-seat duration numbers and matches with the lobe separation and duration figures as you can see in my charts that I posted above... I used data straight from the factory service manuals for my spreadsheets...
Isn't seat to seat duration (advertised) and duration at 0.006 (SAE) the same?
 
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