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carbed 360 magnum, cam advice

Posted By: turboking15

carbed 360 magnum, cam advice - 01/09/13 11:49 PM

First off hello everyone glad to now be a part of the forum.

The motor in question is a 5.9 magnum, .040 over, scat h beams, srp flat tops (142070),.040 thick hg, 2.02-1.65 eq iron heads, light port and polish, m1 single plane, holley 750, 1" open spacer, 1.75" headers 3" collectors

The car is driven on the street but daily driving manners are not my concern, if its a little rowdy im alright with that, i have a boring sheep mobile to drive if i want comfort.

I have been looking at a couple of OTS cams and like the specs on most of them but was also wondering if a combo of a couple cams wraped up into a custom grind would be better? Here are the cams im looking at:

The main one is:
XR280HR 280/288 230/236 .541/.537(@1.5rr i have 1.6) 110* lsa

The next ones wont work due to lifter design but i like some of the specs on them:
XE275HL - 275/287 231/237 .525/.525 110* lsa (1.5rr)
288R - 288/288 243/243 .550/.550 110* lsa (1.5rr)
XR280R - 280/286 242/248 .570/.576 110* lsa (1.5rr)

So my big question is should i go with the xr280hr, a combination of some of the other specs, or am i completely off my rocker and in the wrong direction?

Thanks
Posted By: Duner

Re: carbed 360 magnum, cam advice - 01/10/13 12:10 AM

Quote:

First off hello everyone glad to now be a part of the forum.

The motor in question is a 5.9 magnum, .040 over, scat h beams, srp flat tops (142070),.040 thick hg, 2.02-1.65 eq iron heads, light port and polish, m1 single plane, holley 750, 1" open spacer, 1.75" headers 3" collectors

The car is driven on the street but daily driving manners are not my concern, if its a little rowdy im alright with that, i have a boring sheep mobile to drive if i want comfort.

I have been looking at a couple of OTS cams and like the specs on most of them but was also wondering if a combo of a couple cams wraped up into a custom grind would be better? Here are the cams im looking at:

The main one is:
XR280HR 280/288 230/236 .541/.537(@1.5rr i have 1.6) 110* lsa

The next ones wont work due to lifter design but i like some of the specs on them:
XE275HL - 275/287 231/237 .525/.525 110* lsa (1.5rr)
288R - 288/288 243/243 .550/.550 110* lsa (1.5rr)
XR280R - 280/286 242/248 .570/.576 110* lsa (1.5rr)

So my big question is should i go with the xr280hr, a combination of some of the other specs, or am i completely off my rocker and in the wrong direction?

Thanks



How heavy is your car?
What convertor?
What rear gear?
Posted By: turboking15

Re: carbed 360 magnum, cam advice - 01/10/13 12:46 AM

car is about 3000 lbs +/- 100lbs
no convertor 5 spd
3.55 gears
Posted By: onebaddakota

Re: carbed 360 magnum, cam advice - 01/10/13 02:06 AM

What are the spring on the heads? You can't go crazy on the lift with the hyd. roller setup.
Posted By: turboking15

Re: carbed 360 magnum, cam advice - 01/10/13 02:22 AM

no springs yet, waiting on a cam descision.
Posted By: cudadoug

Re: carbed 360 magnum, cam advice - 01/10/13 04:41 AM

If the guides are untouched, you'll be limited to .525 or so at the retainer.

I like this one, if there isn't a guide to retainer problem:
XR280HR 280/288 230/236 .541/.537(@1.5rr i have 1.6) 110* lsa

I would also consider the switch to an Eddy Air Gap intake.
Posted By: moparacer

Re: carbed 360 magnum, cam advice - 01/10/13 05:36 AM

I used the XR280HR in my budget pump gas magnum build I just finished in December. I used stock 318 heads. I run 1.6 chevy rockers and bought the comp cams cutter to cut the guides down. Had to cut them a lot to get good retainer to guide clearance. I used the 2.2 retainers and mopar P4876062 springs.

My setup is close to yours at 3300lbs and 3.55 gears and it shows some promise as it run 11.38 @ 118 through full exhaust and a LOT of ET left in it.
Posted By: turboking15

Re: carbed 360 magnum, cam advice - 01/10/13 07:57 AM

why would you suggest the air gap over the m1?

Did you cut down the spring seats or just the guides? What is your IH and spring pressures? Any idea how much you cut off the guides?

Also do you have a pn on the rocker arms you used?
Posted By: cudadoug

Re: carbed 360 magnum, cam advice - 01/10/13 09:10 AM

Quote:

why would you suggest the air gap over the m1?

Did you cut down the spring seats or just the guides? What is your IH and spring pressures? Any idea how much you cut off the guides?

Also do you have a pn on the rocker arms you used?



I feel the Air Gap will make a little more torque down low...
Posted By: cudadoug

Re: carbed 360 magnum, cam advice - 01/10/13 09:12 AM

Quote:

I used the XR280HR in my budget pump gas magnum build I just finished in December. I used stock 318 heads. I run 1.6 chevy rockers and bought the comp cams cutter to cut the guides down. Had to cut them a lot to get good retainer to guide clearance. I used the 2.2 retainers and mopar P4876062 springs.

My setup is close to yours at 3300lbs and 3.55 gears and it shows some promise as it run 11.38 @ 118 through full exhaust and a LOT of ET left in it.



Wow...good info here. But WOW!!!...that runs good. Tell us more about your combo.
Posted By: patrick

Re: carbed 360 magnum, cam advice - 01/10/13 03:09 PM

don't know about the EQ heads, but stock magnums don't have a lot of meat on the port roof to cut down the spring seats...when I did my magnum 318, I had the valves sunk about .030 on the valve job, and used Hughes #1110 springs and 2.2L retainers/magnum locks. gave me ~1.64"IH and about .54-.5500" of potential lift before getting into spring binding and valve guide clearance concerns.

I'd see if bullet cams can regrind your existing stock cam, or grind you a new one. I'd use the HR278/340B lobe for the intake and exhaust. magnums have really good intake/exhaust flow balance and don't really need a split pattern cam. this lobe is 278 deg@.006, 226@.050, 146@.2, and .340" lobe lift (.544" with 1.6 ratio rockers). for comparison, the flat tappet comp XE275HL is 275 adv, 230@.050, and 149@.2" lobe lift....

http://bulletcams.com/Masters/HRlobes.htm

and an RPM air gap intake will get you another 20ft-lbs of torque down low compared to the M1 single plane, and should match it power wise up to 5500-6000 RPM
Posted By: turboking15

Re: carbed 360 magnum, cam advice - 01/10/13 10:26 PM

That was one thing ive been looking for and cant find is a balanced cam for the roller motors, everything ots is slpit. Is there a reason for this? Another reason i have been looking at some of the higher duration / lift cams is the static and dynamic c/r that this motor will have. I am looking at 10.87:1 static and 9.8:1 dynamic, and from what i have read the bigger cams will help to bleed off a little to make the motor pump gas friendly.

I appreciate all the great information, im still fairly new to building v8's as i come from a world of turbo 4's, so im trying to learn all i can.
Posted By: patrick

Re: carbed 360 magnum, cam advice - 01/11/13 01:37 PM

if you have good tight quench (.030-.045") it should run on pump 92 with the cam I suggested. may have to limit advance a bit, but my mag headed 318 ran best with only 30 degrees total timing, thanks to the efficient chamber
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