Need cam advice for my 360

[Savage6]

Hey guys,  I have a 360 bored .030 over.  2.02 heads, KB Pistons with Eagle rods, Weiand Excellerator Intake, hooker headers, Crane gold adjustable roller rockers, an Edelbrock 750 carb, Hughes 2500 stall and 3.73 rear end gears.  I just got the car and of course the guy didn't know what the cam specs were.  I am assuming it is a little over-cammed because to get this to idle good in gear I have to have it set at about 1600 RPM's in Park.  For now I am trying to run as much advance as I can, and I have full vacuum running to the dizzy to try and help with the low vacuum.   It will probably have to wait for the winter, but I can always start planning now. 

Any one have any suggestions?   Savage

[femtnmax]

Do some searching on this forum.  Many opinions and good info.
OEM mopar specs for 340/360 were:  360   4 barrel    Hydraulic   268/276 seat duration, 44 degrees overlap, and 430/444 lift.  Duration at 0.05 lift was around 210/220 with 114 lobe seperation angle, so wider LSA for smoother idle, good low speed torque.
Don't say what cylinder heads your using.  To do it right need to find cam that works with your engine parts combo.  Fill out kb-silvolite compression ratio calculator.   For cast iron heads, street use, pump gas, and low elevation above sea level, need to keep static comp ratio about 9.5:1 max, with dynamic ratio below 8:1.  There will of course be opinions that don't agree with these numbers, but I''m building for poor gas and many thousands miles use.
Filling out KB's calculator with a couple assumptions:
Cylinder head volume  72 cc  (stock 340 X head), cc's might be 74-75cc with valve jobs.
piston head volume    5cc   (assumes flat top piston with valve reliefs)
head gasket thickness   0.040  (felpro blue permatorque, they are great gaskets)
head gasket bore    4.15   (approx)
cylinder bore    4.03    (your exact spec)
deck clearance  0  (assumes engine builder knew what they were doing and set quench clearance properly)
stroke   3.58  (stock crankshaft)
rod length   6.123  (stock rod length)
Intake valve closing point   60    (spec for the following comp cam 268AH-10)

KB calculator Results:
static compression  9.7:1  (need mid-premium pump gas)
dynamic compression  8.0:1

for 74cc combusition chamber volume, static ratio drops to 9.5, dynamic is 7.8
for 74cc chambers and pistons 0.02 below deck (typical), static ratio drops to 9.1, dynamic is 7.5    THIS COMBO would work well using regular grade pump gas for street use.   Quench clearance is a little loose, but probably good enough considering many people don't check it at all.

The cam used above is Comp cams magnum muscle cam, grind # 268AH-10, part # 20-309-4.  Seat duration 268/276 with 222/226 duration @0.05 lift.  Valve lift .464/.464.   This cam would not be hard on the valve train, don't need new valve springs, should work well with auto trany, yet still provide more performance than stock.  The intake valve closing angle is 60 degrees after bottom dead center according to Comps camquest.
Using your info, camquest results are:  376 hp @ 5000 rpm, 433 ftlb torque @ 2500 rpm.  Torque curve was nice and flat from 2500-4000 rpm, and torque is king on the street (not some peak hp number).

Ideal set up these days is want the most valve lift for the least cam duration, so the comp cam falls short of this in vavle lift,   but it does well in that you won't need to check valve spring coil biind, piston valve clearance, don't need to upgrade rocker arms/shafts, etc.
hope this helps, and is just my opinion.

[c00nhunterjoe]

if it wont idle in gear unless the out of gear idle is at 1600 then it sounds liek you have a converter issue, what does it idle at in gear?

[Savage6]

It idles in gear at around 750rpm...  The heads are J heads with 2.02 intake..    It will idle around 1100 in park for a few seconds and then all of a sudden just rises to almost 1800rpms without me doing anything. Once i drop it in gear it comes down to 750.  I was wondering if the step up springs need changed in the edelbrock?  It almost acts like the gas pedal is being pushed.  the stall is 2500   ... 

[Savage6]

Thanks femtnmax... that was quite the in depth reply!  I will have check in to that because this thing is a beast.. thanks for helping out

[firefighter3931]

The Engle K56 hyd grind would be a nice match....swap the cam & lifters and you're good to go. Much better vacuum and drivability. It sounds, from your description....that the engine is overcammed.



Ron

[maxwellwedge]

It idles in gear at around 750rpm...  The heads are J heads with 2.02 intake..    It will idle around 1100 in park for a few seconds and then all of a sudden just rises to almost 1800rpms without me doing anything. Once i drop it in gear it comes down to 750.  I was wondering if the step up springs need changed in the edelbrock?  It almost acts like the gas pedal is being pushed.  the stall is 2500   ... 

Sounds like your distributor is advancing and raising the rpm.

[Savage6]

I wish I knew what it was?   I'm just going to listen to Ron and go with the Engle K56 and call it a day.  I've been reading this forum for three years now to fix problems with my charger and now a duster and what Ron says goes!   Thanks again for the help guys...  Savage