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WTruo

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Comp delivered the goods. Can ya please walk me through the numbers and explain to me the profile of this cam? Which specs will I need in order to degree this baby?
 
The 270 H is a oldie but goodie
goodie in that it has minimal special requirements and wears well
it is not as aggressive as the XE series and MUCH MUCH less of a cam as the xennnHL series (which is unfortunaty not made under aaround 275 duration)
The 270 is the duration at .006 lifter rise
you can find the .006 (seat) timing on your timing card- it shows intake closes around 60 degrees AFTER BOTTOM DEAD CENTER or ABDC
not knowing your build the seat timing determines your dynamic compression
If interested post your cranking compression once you get the motor together
The 270 size cams are for moderate compression motors with converter and gears IMHO
what does the comp catalog say?
this duration also determines your low end and torque band- where to shift
If you had a low compression motor like a late 360 we would be looking for a shorter duration and the same lift to get the intake closed earlier and build cylinder pressure They would close around low 50's ABDC

The .050 timings help to show how much power the cam can make and you can also use them to 'degree in" your cam- which you should do but the did not give .050 timings
if they had we could subtract the .050 timing from the .006 and see the "intensity" how quick a cam it is
imho the h series is quicker than stock mopar and about what a MP cam is
A mP cam uses a larger of the lifter which can give faster acceleration- but don't worry about it

So to degree in the cam you are going to have to install a degree wheel and pointer and ve able to turn the motor over by hand in one direction
you are going to have to find TDC on the #1 (or 6 cylinder) and set the pointer to 0
make sure you know if you are on the TDC firing or TDC overlap (exhaust closing -intake opening)
Comp says this cam is ground with the lobes spread 110 degrees and wants it installed on a 106 INTAKE centerline which means that there is 4 degrees advance ground into the cam
so how to find the Intake Centerline
What you do is find the degrees down from the top of the lobe around .050 on both the opening side and the closing side and assume that the centerline is in the middle of these two numbers
Take a look at it a few times and think through it
oh- you need a dial indiacator prallel to the lifter and either put in a solid lifter or not let your lifter bleed down
say you do the procedure and find that your centerline is at 108- the intake would be closing late here 63 degrees ABDC and you want to pull it earlier to 61- figure out which way you have to move the gear on the cam
If your gear moves in 4 degree chunks you might end up with 59 degrees ABDC
which might be better in a lower moderate compression engine with taller gears and tighter converter', heavier car etc
and might be better to leave at 63 with compression on the higher side and lower gears and looser converter and lighter weight-( to prevent pinging) yadda yadda
in otherwords- it depends
if you post up all your build details we could cut down on the yadda yadda a bit
anyway you can find better explanations better than mine
 
The 270 H is a oldie but goodie
goodie in that it has minimal special requirements and wears well
it is not as aggressive as the XE series and MUCH MUCH less of a cam as the xennnHL series (which is unfortunaty not made under aaround 275 duration)
The 270 is the duration at .006 lifter rise
you can find the .006 (seat) timing on your timing card- it shows intake closes around 60 degrees AFTER BOTTOM DEAD CENTER or ABDC
not knowing your build the seat timing determines your dynamic compression
If interested post your cranking compression once you get the motor together
The 270 size cams are for moderate compression motors with converter and gears IMHO
what does the comp catalog say?
this duration also determines your low end and torque band- where to shift
If you had a low compression motor like a late 360 we would be looking for a shorter duration and the same lift to get the intake closed earlier and build cylinder pressure They would close around low 50's ABDC

The .050 timings help to show how much power the cam can make and you can also use them to 'degree in" your cam- which you should do but the did not give .050 timings
if they had we could subtract the .050 timing from the .006 and see the "intensity" how quick a cam it is
imho the h series is quicker than stock mopar and about what a MP cam is
A mP cam uses a larger of the lifter which can give faster acceleration- but don't worry about it

So to degree in the cam you are going to have to install a degree wheel and pointer and ve able to turn the motor over by hand in one direction
you are going to have to find TDC on the #1 (or 6 cylinder) and set the pointer to 0
make sure you know if you are on the TDC firing or TDC overlap (exhaust closing -intake opening)
Comp says this cam is ground with the lobes spread 110 degrees and wants it installed on a 106 INTAKE centerline which means that there is 4 degrees advance ground into the cam
so how to find the Intake Centerline
What you do is find the degrees down from the top of the lobe around .050 on both the opening side and the closing side and assume that the centerline is in the middle of these two numbers
Take a look at it a few times and think through it
oh- you need a dial indiacator prallel to the lifter and either put in a solid lifter or not let your lifter bleed down
say you do the procedure and find that your centerline is at 108- the intake would be closing late here 63 degrees ABDC and you want to pull it earlier to 61- figure out which way you have to move the gear on the cam
If your gear moves in 4 degree chunks you might end up with 59 degrees ABDC
which might be better in a lower moderate compression engine with taller gears and tighter converter', heavier car etc
and might be better to leave at 63 with compression on the higher side and lower gears and looser converter and lighter weight-( to prevent pinging) yadda yadda
in otherwords- it depends
if you post up all your build details we could cut down on the yadda yadda a bit
anyway you can find better explanations better than mine

The engine is a 360 thats in a 1986 d150. The truck is completely stock. It's a 8 1/4 w/ 3.21 gears. I will do a compression check this weekend when I'm replacing the exhaust.
 
That cam is too much for a stock engine in a truck, with high gears.
Go with something smaller.
 
It is mild, but mild in what?
In a low-compression 360; in a 4000 pound truck with a 1750 stall TC and 3.21s It's gonna be lazy out of the gate. The Ica is 61* which is gonna kill the cylinder pressure of an already pressure-handicapped engine . It probably won't wake up until after 35mph.
Go back to post #4.
You gotta choice to make;
either pump up the compression, or get a Hi-stall TC, and deal with the 3.21s
xxxxxxxxx xxxxxxxxxxxxxxxxx xxxxxxxxxxxxx
I have an 84 D100 318/904/8.75
with a stock 1973 long-block low-compression 318LA. ( just a 4bbl on it)
I installed a 2800TC, 3.55s, AND an A998 with a 2.74 low gear. This gets her off the line reasonably well with a starter gear of; 2.74x3.55=9.73 , and 28" tall tires. We are at 930 ft elevation. Yes it does spin both tires, now, but not for all that far. I had to fab up a pinion snubber to stop the wheelhop.

If you upcam one of these smog engines,with same type cam,and no other changes, you will, almost without exception give up cylinder pressure. About 1.5psi per degree Ica increase or about 6psi per cam size.
A cam size is about 7*.
So,in your case going from a factory 252@.008, to a 270@.006 is close to 1.5 to 2 cam sizes, so close to 10 psi loss. That is a lot of lost pressure. And that is mostly what makes her lazy. And this laziness does not improve with rpm,until she is spinning pretty good.
The rest of the low-rpm laziness is in the factory lo-stall TC, forcing your engine to operate at an rpm where it has very little power, which was just made worse by the lowered cylinder pressure.
And then there are the 3.21s forcing the lazy bottom-end, to way up the MPH scale .

If yur looking for off-the-line giddy-up, your first go-to should be a higher than factory stall TC, and second would be a bigger number rear gears plus a SureGrip.
Then dual exhaust and a 4bbl. Hedders are optional with the stock engine.
Lastly is a cam with matching compression upgrade, and usually hedders. With possibly another bigger rear gear to compliment it.Because every next bigger cam moves the power-peak up about 200 rpm,which sucks the bottom up about the same, and after 2 or 3 sizes, the truck is getting lazy off-the-line again.
So yeah in a proper combo, that 270/270/110 is a mild cam...
But in a pressure challenged engine, it's not gonna bring power at low-rpm. It just can't do it without help.
And finally, I should be fair and say;
if you install skinny tires, or hard compound tires, or pump up the tire pressure, and are able to get both tires spinning, then even a lazy engine can be fun,lol.
My D100 with it's stock smoggerteen, spins pumped up 275/60-15BFGs a goodly ways,lol, making it fun. Fun heck-ya.... but not fast.
 
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It is mild, but mild in what?
In a low-compression 360; in a 4000 pound truck with a 1750 stall TC and 3.21s It's gonna be lazy out of the gate. The Ica is 61* which is gonna kill the cylinder pressure of an already pressure-handicapped engine . It probably won't wake up until after 35mph.
Go back to post #4.

I'm not trying to build a hot rod. All I want is a throaty sound.
 
Never build an engine for sound, a performance engine will sound like one.
 
I have same cam but solid in our 67 273, 904 323sg. A combo of too much cam, not enough gear and converter in my case.
No bottom end.
 
Old Hemi grind 484/484 I went down that rabbit hole as a stupid teenager.
Stock 318 4-speed 3.91 gears, to top it off I but bigger chamber J heads on it.
POS would only do 10.00 flat in the 1/8 mile.

It was a dog, but sounded like a thrash machine.

Never again, when I buy an off the shelf cam, I buy the next one smaller than the manufacturer recommends.
 
Damn, I feel so stupid right now. I should have came to ya first before I called up comp.

This truck will never see the track. All this truck does is get me to the gym, store, the next town over.
 
... All this truck does is get me to the gym, store, the next town over.

Eventually..

It's now going to burn a lot more gas doing it and be a ***** to merge on the highway. But at least it will make your eyes water and your tailgate black while sounding faster than the prius that will outrun you to the next light :poke:
 
Eventually..

It's now going to burn a lot more gas doing it and be a ***** to merge on the highway. But at least it will make your eyes water and your tailgate black while sounding faster than the prius that will outrun you to the next light :poke:

Lol, damn.
 
Then call Comp up and tell them the cam "they recommend" will not fit your needs and exchange it for something smaller.
 
Eventually..

It's now going to burn a lot more gas doing it and be a ***** to merge on the highway. But at least it will make your eyes water and your tailgate black while sounding faster than the prius that will outrun you to the next light :poke:
That Prius will smoke him.....
 
Lol, damn.

Mostly just giving you crap because I'm frustrated by my w150 that can barely cross an intersection before the light changes.. No gear and a stock converter with bigger tires definitely makes it slower than my lawn mower to 15mph..

A new converter and better gear would make it more livable but so would more compression or an earlier IVC. If I were you, I'd be considering advancing that cam a bit more than the 4 degrees comp grinds into it. An additional 2 to 4 will help the low end and still chop, and it'll still burn more gas, but at least you won't feel so stuck in the mud every time you leave the line..

Depending on how much you like to wrench, might be worth installing per comp, then try advancing a bit. All you've got to lose is time and permatex..
 
Then call Comp up and tell them the cam "they recommend" will not fit your needs and exchange it for something smaller.

This is seriously the better choice. One of their "thumper" cams might get you where you want to be, but it'll still eat gas like never before.

Will sound good though and they should keep more low end in it. You'll still wish for more gear and converter though. It's tough to get that much steel moving..
 
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