I think I'd draft a form letter and send it to several cam grind companies to their tech support. I would think they have the specs if they grind replacements. Other than that one could indicate the cam on V-blocks with a degree wheel attached. The standard rocker is 1-1/2 the lift.
I'd be curious if it comes close to any of these in the "Updated" area.......
So here's is what I measured on my cam. Full disclosure here; this is the first time I did this procedure (albeit after watching at least a dozen Youtube videos) so consider the data "suspect"... I took my measurements on #1 cylinder and also ran a quick set on the #4 cylinder as a reality check - and the results were quite close.
As suggested above, next step is I'll check in w a few cam manufacturers to see what they can do for a replacement. Not sure I'll replace it but let's see how it runs after I finish the rebuild. I'm wondering if there is a more optimal cam for a sub-3000 RPM 42' 15 ton 10 knot boat? Better fuel economy would be nice but I'm not sure that is realistic. Anyway, FYI.
- assume 70’s era cam (engine is 1977) but unclear if it is stock Mopar or not
- using hydraulic flat tappets
- for standard rotation [starboard] engine
#1 Cylinder Intake
Max tappet lift 0.286”
Valve lift 0.429” (using 1.5 rocker ratio)
Cam baseline run out 0.0” (no deviations off 0)
Opens @ 0.006” 15 deg BTDC
Closes @ 0.006” 73 deg ABDC
Duration @ 0.006” 268 deg
Centerline Below Max 0.020” 086 deg
Centerline After Max 0.020” 144 deg
Centerline calculation 111 deg ATDC (crank)
#1 Exhaust
Max tappet lift 0.303”
Valve lift 0.455” (using 1.5 rocker ratio)
cam baseline run out 0.0”
Opens @ 0.006” 75 deg BBDC
Closes @ 0.006” 51 deg ATDC
Duration @ 0.006” 306 deg
Centerline Below Max @ 0.020” 216 deg (on the wheel ATDC)
Centerline After Max @ 0.020” 274 deg (ATDC)
Centerline calculation 245 deg ATDC = 115 deg BTDC (crank)
Lobe separation = 111 + 115 = 226 deg (crank) = 113 cam deg
#4 Cylinder (for confirmation of above measurements on #1)
Intake
Max tappet lift 0.287”
Valve lift 0.431” (using 1.5 rocker ratio)
Cam baseline run out 0.0”
Opens @ 0.006” 15 deg BTDC
Closes @ 0.006” 75 deg ABDC
#4 Exhaust
Max tappet lift 0.301”
Valve lift 0.452” (using 1.5 rocker ratio)
Cam baseline run out 0.0”
Opens @ 0.006” 74 deg BBDC
Closes @ 0.006” 55 deg ATDC