1970 Dodge Dart 318 upgrades

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that's you standard non magnum 440 cam used for many many years- started off as a 10:1 cam later a smog cam
340 HP cam
.004 20 79 79 30 (50) 279/289
.050 -8 37 46 -6 210/221 some say 209/220
diff 28 40 33 36

440 Magnum
302/321 213/225 some say 324 duration on the exhaust 004
298/308 .006 Linati version
268/276 adv comp says 28 60 27 72 @006 but these may be mopar numbers
 
Thank you.

Different question: Is there any source for detailed profile info, like lifts every 5 or 10 degrees? (Reason: I started a writing a program a while back to compute valvetrain accelerations and forces but it needs detailed profile data. I have not ever called a cam maker yet for this as the progress is stalled; continuing on that little project keeps getting put off until retirement; work is too busy now.)
 
I have cam doc info for all the factory cams
however the only two I have access right now are a couple of DC cams including the Early (evidently) DC 260
I also have the Moon and Jones Cams
here is a little more data for the DCR guys
From Melling site
SPD 25 360 single pattern cam- intake and exhaust the same (this year)
22 76 62 37 278
-7 29 31 -9 203
29 31 intensity .004< .050 opening sides intake and exhaust
49 46 - intensity .050 >004 negative- closing sides

SPD 22 340 360 HP
20 79 79 30 279/289
-8 37 46 -6 209/220
28 33 intensity .004< .050 opening sides
42 36 - intensity .050 >004

SPD 20 318
12 72 57 38 264/275
-20 20 24 -12 180/192
32 33 intensity .004< .050 opening sides
52 50 - intensity .050 >004

you can add the intake and exhaust separately to get total lobe intensity for in and ex
Jones 264@.004 202@.050 total intensity Opening + closing 62 120@200
DC 260 284@.004 212@.060 total intensity 72 115@200
but jones holds to 50 % more duration at .275 just below the centerlines

SPD 11 B/RB
22 74 74 39 284/293
-7 33 40 -11 206/209
29 34 intensity .004< .050 opening sides
41 50 - intensity .050 >004 closing sides

SPD 31 B/RB HP/Magnum
26 96 83 61 302/324
-6 39 50 -5 213/225
32 33 intensity .004< .050 opening sides intake and exhaust
63 66 - intensity .050 >004 closing sides

I put intake closed @.004 in bold
does not take much to see the excessive large intensities especially on the closing sides
This affects Dynamic compression on the intake and exhaust gas reversion on the exhaust
you can also see why advancing these cams may help apparent torque but really hurts the overlap/ reversion problem and causes more heat in the exhaust- as if that's possible
realtively speaking you can compare with the comp lobe catalog but comp uses some non stated numbers for their "intensities" show as (total) Intake exhaust)
most likely .006 and as has been shown elsewhere there can be a big difference between MOPAR, 006 and 004
IMHO you do not start to build compression till the valve is fully closed
the flow stalls then reverses if it is open even a tiny bit (piston is coming up- compression is almost trapped and is increasing rapidly
you can get exhaust torching with slow exhaust opening
etc
 
Last edited:
nm9stheham said:
Thank you.

Different question: Is there any source for detailed profile info, like lifts every 5 or 10 degrees? (Reason: I started a writing a program a while back to compute valvetrain accelerations and forces but it needs detailed profile data. I have not ever called a cam maker yet for this as the progress is stalled; continuing on that little project keeps getting put off until retirement; work is too busy now.)
Click to expand...
Try Rick Jones at Controlled Induction and introduce yourself
 
Johnny Dart said:
This is a totally stock, matching numbers 318 that came in my 70 Dart.
I added nothing but bolt on parts. Ede performer intake, ede 600 cfm, 340 hipo manifolds, dual exhaust/40 series flowmasters, Mopar Performance elec ign. Stock cam, stock 2.76 gear.
I acquired all these parts from old fashioned horse trading. The 340 manifolds being the majority of the cost. But in car terms, very inexpensive hp. This car was a kick in the *** to drive, easily burning rubber all the way down the street. One of my favorite motors, and setups. Anyways, you got the motor out, and you want to hop it up. Might as well go the distance and add a 4bbl. You will be happy you did.

View attachment 1715192955
Click to expand...
That is beautiful!!!
 
Here is your best bet with a low budget 318, with a top end rebuild. I doubt ANYONE will disagree.

1. Assuming bottom end is tight, perhaps with a little smoke and decent cyl pressures of over 145-150, leave it alone
2. Thin head gaskets
3. Machine heads - Bowl port and valve job, and max decking
4. Plenty of used Al and CI 4-bbl intakes for cheap
5. Cheap small carb, 600-650
6. Dodge dakota CI exh manifolds into dual exh
7. Assess Dyn CR, which should be around 8:1, and match the right cam
8. Enjoy
 
good tip on the Dakota exhaust- they work well
but they dump in different places than the 360 so check clearance with your steering box
3" single exhaust will also work
"and match the right cam"
 
nm9stheham said:
Now THAT is interesting... that 23-26 degrees extra duration for the .004" vs .008" duration is pretty important. Which number is best for DCR - .004" or .006" lift at closing - is something that has to be guessed at... and it changes with RPM I am sure, being that we are wanting to know when the cylinder 'effectively' stops leaking any significant pressure.

I always wondered about the symmetry opening vs closing, and always assumed they were equal. I am a bit confused as to the reference to the '440 cam', with all that assymetrical closing vs opening ramp. Which cam is that?
Click to expand...

IMHO the valve has to be completly shut to start building compression
I've posted elsewhere how slow the factory cams are (noise, longevity, no bounce after the springs weaken)
Most of the newer aftermarket cams are Asymetrical
but the DCR simulations are invaluable even if not perfect
I'll go backover the thread later and try and address a couple of your other questions
Rick Jones Controlled Induction software is much more sophisticated but the one AJ uses makes great contributions
 
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