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
