cam lobe seperation question

[andy74]

if 2 cams have the same lift and duration,but one has 108 lobe sep. and the other has 114, wihich one will have more bottom end torque? i have a chance to get the newer grind mopar 284/484 cam,and i was told it will have less low end with wider lobe seperation? ron,neil, ken any one?   

[John_Kunkel]

A wider LSA will give a smoother idle and better low end torque.

[Ghoste]

So what is the LSA in the new and the old 284/484 cam? 

[firefighter3931]

A wider LSA will give a smoother idle and better low end torque.

The wider lsa spreads out the powerband. The narrow lsa will make the engine hit harder at the sweet spot....but it will be softer below that sweetspot than an identical cam specced wider. So at 2000 rpm the 114 lsa will have more torque but at 3000 it might have less. Generally the wider lsa grinds make power sooner and hold it longer. Hope that helps.

Ron

[Ghoste]

And by rereading Andy's post, I guess my question was already answered.  Since I have the older one in mine, I am assuming a 114 LSA.  Any guess where this sweet spot should be in a 383?

[Runner]

ghoste are you talking about the 108 las .484 mp cam?  if so the "sweetspot" will start about 2700-3000. they are absolute pigs in a 383 below 2500 rpm, just not enough stroke.  when i first put my 383 together with the 484 (108 version) it had exhaust manifolds and a 2000 stall converter. it would lumber along until it hit about 2700 then it was like someone went from 1/4 throttle to full throttle instantly. when i went to a 3k converter it was much better, no more dead power. whne i went to a 3800 converter it was much, much, better.

[Ghoste]

I truthfully don't know what is in there for LSA(but you're right, that is what I meant in the other post).   The cam has been in there now about ten years or a little less.   When did they go from a 108 to a 114?
There is no question that my car doesn't begin to turn on until half track but I sure don't want to put more converter in the car.

[Runner]

10 years ago all that was available was the 108 cam.    as far as the converter goes, i have that 3000 stall 11 inch converter behind my 383 in my 68 satellite now with 3.23 gears. it drives just fine. id bet you would be pleasantly surpised at how much better your car feels, and how little it acually affected drivability.

[Ghoste]

It's more a case of having already spent money on a converter and rebuilt the trans a couple of times I do not want to pull the dman thing out again.
The converter I have was supposed to be a tight 2800.  It's more like 2000 but of course, as this thread hijacking has already shown, I don't have a lot of low end torque in my car.  Which is nice considering how much more a 1st gen weighs than a 2nd or 3rd.
At least I'm learning more about this combination and what it will take to make it work.

[Runner]

i had my 383 in my car for 10 years, first time at the track it ran 15.80s i tried a few different intakes while i ran it but never got any real big gains, however gears, and converter ALWAYS made it faster. by the time i pulled it (becsause that 484 cam lost a couple lobes after 10  years) it had ran a best of 12.49@109 and the valve covers came off mabe 4 times in 10 years, that was to fix leaks a couple times and to change covers to polish mp units.  guess my point is, it ended up running pretty hard and i never really changed anything on the long block, just the tune up, gears , and converter.  i learned ALOT with that old motor.

[Ghoste]

It's funny because my experience has been the opposite.  Intakes made a difference but converter and rearend just seemed to be negligible.  It's mostly because of the way those things affected the rest of the combination and that comes down to tuning in many ways.  I still just found it funny.

[andy74]

you can get the 484 cam in either lobe seperation,i had spoke with ron about a month ago,and he actually reminded me about them.the old style 108 is part number 4120235,the new one is p5007697.

[andy74]

sorry to bring this back up, but with the current conditions at work(SLOW)i have way to much time to think!the new 440 is almost ready,.030 over,forged flat tops,measured out to 9.3 to 1 with my heads,polished and ported 906s,i have an edelbrock torker intake(not a tq2)edelbrock 750 carb,and hooker headers,1 7/8 primary,2 1/2  inch collecter,full 2 1/2 inch exhaust,thrush turbo mufflers,a 2500 stall convertor in side a new rebuilt 727,and 8 3/4 with 3.55s,sure grip-27 inch tall rear tires.Now i have to decide on the cam for good(for now)because i can charge the mopar stuff i have to go with one of them-should i go with the 114 sep. 484,or the older style,108?i can also get the 238/474,the pricing is the same.i have said it before, its no drag car,just my back roads blaster,and i want a decent amount of power,for least amount spent.my running total is less than 4 grand,as i traded a whole bunch of labor,parts etc for the pieces and parts. any one care to chime in?

[Runner]

if it was me id call dwayne porter at porter racing heads (you can go to moparts and look him up as fast68plymouth) and buy whatever cam he sugests. i have never heard anyone say he "missed" there combo.    if i was to buy a 484 cam id buy the comp version.

[firefighter3931]

Andy, if you had to choose between those 2 cams....the 114* lsa would be better. But, it's really still too big for a heavy car with a mild stall and mild gearing. The Crower HDP271 is your cam....pn 32242.

It is a split pattern grind with 222* intake/232* exhaust, 112*lsa, and ~.500 lift at the valve. Power brake friendly with good manifold vacuum and street manners and a slight lope at idle. Very good bottom end power and will pull hard to 5800 rpm or so. Well matched to the converter, compression, intake manifold and exhaust system you plan to run in this combo. I used the next grind up (hdp282) but had more compression, more stall and more gear.

Summit racing has the hdp271 priced at $140.00....fyi.

Ron


Ps. I agree with Mike (Runner) on using Fast68 for a custom grind....funds permitting. Ask him about the hdp271....i know for a fact that he ran it in one of his old motors.

[Ghoste]

So a "mild" converter would be anything less than what?  2500?
Runner, did you do much long distance highway driving with the 3000 in your car?

[andy74]

im going to check on the cam you recomend ron,do i need adjustable rockers with that one?

oh ghoste,i think these guys mean that a mild convertor,compared to a 3-3500 drag strip type

[Runner]

i didnt do alot of driving on long trips with the roadrunner and the 11 inch, however its now in my 68 satellite and i drive it as my dialy driver. ive driven it several times on 200+ mile trips with out an issue.  it is acuallly rated at 2500 but it foot brakes to 3000 behind both of my 383s.

[firefighter3931]

im going to check on the cam you recomend ron,do i need adjustable rockers with that one?

oh ghoste,i think these guys mean that a mild convertor,compared to a 3-3500 drag strip type

Andy, the factory stamped rockers will be fine with this grind.

Ghoste, for me anything under 3k stall is mild. With a quality converter like Turbo Action, PTC, Dynamic....you can run a higher stall and not even know it's there until you mash the pedal. Deeper gears also help the converter to firm up at lower speeds.

Ron

[Ghoste]

I have 4:10 gears in the car.  My big worry is the five hour drive to Columbus every year.  A converter wouldn't need to be slip much to burn up a trans in five hours.

[firefighter3931]

A converter wouldn't need to be slip much to burn up a trans in five hours.

All converters slip....unless it's a lockup style trans like they used on the later cars. The key is using a quality converter that is efficient and a reasonable approach to cooling. This means a deep pan and a big external cooler. I have friends that drive 8in 5k stall converters on the street and have never burned one up. One guy took his on a 200 mile spin and had no issues with overheating. The tranny usually runs coolest at hwy speed....the idling around in traffic is what can really overheat the trans. From a converter manufacturing standpoint....it's better to tighten up the stall on a smaller diameter converter than it is to loosen up a larger one...increased efficiency = less heat.

Ron

[cudaken]

 My 70 Cuda has 96,000 miles on the engine and trans with a TCI 3500 stall and did a lot of long hauls with it. Say 700 miles in 2 days and no ill effect. It has a stock pan but a seprate tran's cooler. Slipage happens more at lower RPM's.


                         Cuda Ken

[Ghoste]

Okay.  That's helpful.  I was thinking of that highway rpm where it's not quite at it's spec'd rpm.