cam question

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You've still never SAID DIRECTLY what engine this is. So any advice here could be WRONG.
 
My 302 heads with stock retainers had .487 clearance with the umbrella seals installed. So you will be close but like already said get the right springs you should be fine. I recommend comp cams 901-16 springs.
 
My 302 heads with stock retainers had .487 clearance with the umbrella seals installed. So you will be close but like already said get the right springs you should be fine. I recommend comp cams 901-16 springs.
Did yours have rotators?
 
i run ported and matched 302s with 1.60 exhaust valves on my 360, it keeps pulling til i back off at 6000, with the 284/484 in a 318 with these heads it would wind up to 7000 no problem. with present cam ,489 lift from bullet racing and previous MP cam i ran comp 901s as per engine shop recommendation.these heads will flow with good velocity, never mind the number crunchers, try things out for yourself and see what happens
Its fine if you disagree with my opinion, but just to give you a little background (Cliff's note version)....I've said this in a few threads around here...short version is, I've run ported 302's and ported J's on the same motor...the 302's were half a second slower in the 1/4 mile compared to the J's....that's a LOT slower (in case you are not a drag racer).

You rev that thing up to 7k with that small cam.....there is just no reason for that (just saying). Heck, I don't spin my low 10 second small block motor up that high unless I'm running 1/4 mile, and then its only because it has to at the stripe (4.10 gears, 28" tire, do the math) at ~ 129mph, I shift at about 6200rpm (264-268 @0.05 cam).
 
guys that take issue with 302 heads, have you done any porting to them before running them?
 
nuttun but hate here for the 302 heads!! if you can port them and install bigger valves you can get 400 hp! lotta folks round here think you gotta buy W2 or eldeblock or indy heads to build a street car....
 
guys that take issue with 302 heads, have you done any porting to them before running them?


Nope. I refuse to port that head. It sucks. Grinding on them minimally reduces the amount of suck they are.

Do what Mopar Official told you a long time ago. Stuff those castings up someone else's butt and buy the correct 360 head. Leave the 1.88 valve in there and put the grinder away. It will run a ton better with way less money and time wasted.

I just don't get the hard on so many guys have for that emissions head. Part of it I know comes from reading so called hot rod magazine article and now with the web it's even worse. Just because a chamber is of the open variety doesn't make it a bad head, and just because a chamber is of the closed variety doesn't make it a good head. That's just rediculous thinking. That chamber is marginal a best and you can grind until you hit air, coolant, exhaust...whatever and that port will still suck.

Also, it doesn't take a very long search to learn that a "wide" LSA does NOT make more bottom and mid range power and torque over a "narrow" LSA. In fact, it is quite the opposite.

I used quotation marks because who gets to determine what is "wide" and what is "narrow"? Beats me, other that the fact that at this point, we get to work with LSA's from ~102-116 or so. So a 110 LSA is really a mid LSA if you like picking the fly poop out of the pepper. And the 110 was selected as the de facto LSA for about 95% of their shelf grinds not because it's better. No, hell no. They did that because they know that virtually 100% of their cores will take a 110 LSA without issue. When you get down to a 107 LSA, you start setting aside probably 30-35% of the cores because you can't fit a 107 LSA on it. Get to 105 and 97% of the cores won't take it. The decision was purely profit based (and I'm fine with that, but the consumer needs to know why it was done) and not based on a correct LSA for most anything, especially with OE type heads.

That said, I want to point out that LSA should be the result of what the correct TIMING number are, and not some arbitrarily picked number.

Let's take two cams. They have the exact same timing. Exact same. One is on a 108 and the other is on a 112. What does that tell you??? I know what it tells me. Let me say I wouldn't understand this except for the late Harold Brookshire, who was the owner of Ultradyne Racing Cams. He also made lobes for a number of companies before he died. In fact, the Lunati VooDoo line of lobes are all Harold's lobes.

So.....to take that 108 LSA cam and make it a 112 LSA what happened? You have to retard the intake lobe, advance the exhaust lobe or some of both.

The opposite is true. To take the cam on the 112 LSA, you have to either advance the intake lobe and retard the exhaust or some of both? Do you see that?? It is 4 AM right now, and I'm not feeling good so I may have the adjustments incorrect but someone can come along and clean that part up. The point is this: you can't change the LSA without changing the timing.

The correct way to pick your LSA is use all your numbers and then, and only then, set your intake open and closing points, and your exhaust opening and closing points that are optimum for YOUR combo and then whatever the LSA is, it is.

You'll get the right cam then, and not some screw ball cam with screw ball timing just to get an "LSA" that someone thinks is better.

Sorry for the long post.
 
nuttun but hate here for the 302 heads!! if you can port them and install bigger valves you can get 400 hp! lotta folks round here think you gotta buy W2 or eldeblock or indy heads to build a street car....


You coulda had another 50-60 HP if you used those 302 heads as dump filler. Why give up power? I just don't get it.
 
I found the MoPar 302 head to be an excellent unit to have ported for use on a 318 engine. They do not flow like a worked up 360 head. But on the smaller displacement engine and within reason for the typical street hop up to minor brawler, there excellent.

If you wanted to try and actually make a 318 into a little killer of a mill, step up in the head department.

Air flow IS power! So long as it is quality air flow.
 
Also, it doesn't take a very long search to learn that a "wide" LSA does NOT make more bottom and mid range power and torque over a "narrow" LSA. In fact, it is quite the opposite.
I like this statement.

For the rest of us,lol
A wide LSA has a tendency to push the ICA later and later, which steals compression degrees. which reduces trapping, and with NO OTHER CHANGES, softens the bottom end, and leads to higher stall TCs and such. This is terrible for a heavier street-machine with a small engine. Something like a Barracuda 318 at 3600# car and driver. I have always been confused with the why of Mopar's decision to run the 114LSA 340 cams, and why they stuck with them in the 73 up low-comp engines..
On the street with street gears, and a 4-speed; I have never been able to reconcile Wide LSAs because at best, the run to 65mph is ~1.5 gears. So I'd rather have the down-low torque, of a narrow LSA, coupled with a few more ponies at the top, than the alternative with a "wide" LSA.
OK I get that the auto guys can get away with it, by running a hi-stall, but that does nothing for the lost power spike. Plus the Wide LSAs kill the overlap cycle, that headers can really exploit.
And IMO, hydros are about the worst choice for a NA streeter. Yeah they're quiet, and they're maintenance free; but they cost you in every other way.
So a wide-LSA hydro cam, of all flat-tappet cams, for a NA street-performance is, IMO, the least performance oriented, and especially so when installed in a lo-compression street engine; so my question is why in blazes did Mopar stick them into the Low-c 340s?
Oh I know............... the light just went on. Firstly is the 340-specific idle-sound,and then; what year did Mopars go to EGR valves and/or airpumps? Another strike against wide LSA cams.
Like YR said, 110s are mid-pack.
xxxxxxxxxxxxxxxxxxxxxxxxxx
And IMO, the widest I would ever run. My next cam will be a "narrow" LSA solid flatie, with "lots" of overlap,lol.

Here's some food for thought; For my next cam, I'm liking a solid at;
284/288/on 106. This by the math generates 74* overlap, and this cam may have .050 numbers of 246/250
But the spec is say at .006 , and the actual seat-closed to seat-closed might be
296/300 but after lashing might be
266/270 with an Ica of 58*.

Lets compare that to the same 284/288 but on a 114, and now a hydro;
seat closed to seat-closed might be 310/316, and the overlap maths to 58*. The ramps are typically 44* so at .050 it looks like
244/248/114, but the actual closed intake might not be until 81degrees!
Notice the .050s are very very similar
Now lets install these in an 8/1 360.
First the solid;
Static compression ratio of 8:1.
Ica of 58*, elevation 500ft

Effective stroke is 2.93 inches.
Your dynamic compression ratio is 6.73:1 .
Your dynamic cranking pressure is 127.58 PSI..............................127.6
V/P (Volume to Pressure Index) is 113 ......................................... 113
then the hydro;
Static compression ratio of 8:1.
Ica of 81*,@500ft

Effective stroke is 2.33 inches.
Your dynamic compression ratio is 5.56:1 .
Your dynamic cranking pressure is 98.01 PSI................................. 98
V/P (Volume to Pressure Index) is 69 ........................................... 69

to get the pressure back up to match the solid, I get
Static compression ratio of 9.8:1.
Ica still 81*@500ft

Effective stroke is 2.33 inches.
Your dynamic compression ratio is 6.73:1 .
Your dynamic cranking pressure is 127.58 PSI.............................. 127.6
V/P (Volume to Pressure Index) is 90 .......................................... 90
But check out the VP is still in the basement at 90

To max out the pressure at say 165psi
Static compression ratio of 11:1.
Still 81*/500ft

Effective stroke is 2.33 inches.
Your dynamic compression ratio is 8.16:1 .
Your dynamic cranking pressure is 165.15 PSI.................................. 165.2
V/P (Volume to Pressure Index) is 116 ............................................ 116
notice the still weak 116vp

So what about the solid? Glad you asked
Static compression ratio of 9.8:1.
Ica now 58*, still 500ft

Effective stroke is 2.93 inches.
Your dynamic compression ratio is 8.20:1 .
Your dynamic cranking pressure is 166.23 PSI. ................................ 166.2
V/P (Volume to Pressure Index) is 147............................................. 147
Notice the killer 147VP

What do the numbers mean?

Well firstly the .050 numbers come out near identical, so the absolute power numbers will be very similar........ if they also had same overlap.And they do compare well with the 56* of the solid to 58* of the hydro. So far so good.
But check out the VPs; of 113solid to 69hydro, both at 8/1 Scr..... Or of 147solid/90 both at 9.8 Scr .. So what's that mean?
Well VP is a measuring stick we use for the bottom half of the rpm range, and these numbers clearly show that the solid to be 63% stronger in that window.
Now tell me, How much time does your streeter spend in that zone?
Well with an automatic, you can run a 3500TC and the only time your engine will be there, it is also not gonna be at WOT, so nobody cares.
But if you have a manual trans, you are gonna be in that zone like 95% of the time.
Next is the difference in LSAs. The narrow on will make a lil more power at the peak, and a lil less at the bottom, so the curve gets tilted in favor of the manual trans 4-speed which has a narrower powerband requirement... and the bottom end loss is eclipsed by the very strong VP... so winner to the 4-speed. For the automatic, the lower end id erased by the 3500TC, so no big deal there, either way. But, the trans has a 1-2 powerband requirement of 59%.. That is to say if you rev your auto to 5800, then on the 1-2 shift, the Rs will fall to 59% of that or to 3420, or in this case to 3500 plus, which is a powerband requirement of ~2400rpm. In other words your engine better be making some torque down there. Whereas the 4-speed will drop to 72% or from 5800 to 4200 which is 1600rpm so it doesn't need a wide powerband.
And now the hammer;
With the solid, the power extraction will be about 118*, compared to the hydro at 101* .. Guess which one is gonna suck gas big time! Hyup the hydro.
So with the hydro, and an automatic with a 3500 TC, and say 3.55s, the engine will be at ~2870@65mph, and sucking gas to beat all. Whereas, the solid with a manual trans has such a preponderance of low-rpm power that if He wanted to, he could run 2.76s But you know, I like to be fair, so with 3.55s, it too will be running 2870. The difference is that the solid will have the carb nearly closed and is running barely off the idleports.... whereas the hydro/auto will be running quite a bit further up the transfers.
So that's a double whammy to the hydro; first is low VP, and second is the wide throttle-opening.
With all that VP. the solid/manual trans could easily run an overdrive, whereas for the hydrp/auto, an overdrive would just make things worse; .69 x 2870=1980, and I doubt with a VP of 69 she could pull that, I mean even a slanty has better VP than 69 (87 IIRC) and it has a hard time to cruise 65 at under 2000.

So the point is this; there is absolutely no downside, performance wise, to running a big solid-lifter cam on the street, and you don't need the big compression numbers...... so what you didn't spend on new hi-comp pistons, you can now spend on the valve gear.

That's my story and I'm sticking to it,lol.
 
Ok, I just read all of post 40.

THAT NEEDS TO BE A STICKY AT THE TOP OF THIS FORUM, THE PERFORMANCE FORUM, THE BIG BLOCK AND /6 FORUM.

I'm my humble opinion, that post is one of the easiest to read, well laid out, well written threads I've ever read. And the MATH proves the thinking.

Sticky that post. PLEASE!!!
 
AJ...just because I hate math (I can do it, but I hate it's) would mind working up the numbers for my combo?

TIA.

340 CID
11.08:1 actual measured CR
281/281 255/255 .620/.620 105 LSA 105 ICL
1.6 rockers

What does the math say???
 
Give him the timing events @.050 or work the calculators yourself and get the answer quicker.


I did. 281/281 seat and 255/255 at .050

I hate math, even with a calculator. I'm serious when I say I'm more a slide rule guy. In fact, my wife has been grinding on me to get a smart phone. She is lucky I have a cell phone. In fact, when we met I didn't have a cell phone. I only got one when we became engaged. And when this old flip phone I has goes to the big phone garbage dump in the sky, I'll never get another one. I'll be back to land line only.

Oh, how I fawn for that glorious day!!!

Yup, I'm real old school.
 
I did. 281/281 seat and 255/255 at .050
.
No, like the cam card below.
1F7E7972-9398-4973-A596-0ACE0B6054BD.jpeg
 
And yes, I know Jim spelled "break" wrong. He bone headed it because I called him on it. We both had a good LOL on that one.
 
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