ms3 or ms4
10-26-2014, 09:09 PM
#21
I know a very popular combination for a while was the PRC STG 2.5 5.3 heads and MS3 cam. No flycutting involved, and the added compression really helped stretch out the power in the lower RPMs.
I still run the MS3 with stock heads, and it does pull hard up top, but even with 4.10 gears it still feels semi sluggish to me. This is why I will be swapping to more of a medium sized cam, with more useable power on the street.
I still run the MS3 with stock heads, and it does pull hard up top, but even with 4.10 gears it still feels semi sluggish to me. This is why I will be swapping to more of a medium sized cam, with more useable power on the street.
10-26-2014, 09:22 PM
#22
You'll have to flycut with either if you add milled heads. I flycut. It's not that big of a deal.
But the thing you're neglecting here is the value events. A 346 LS1 with cathedral port heads and a LS6/FAST intake manifold likes an intake valve closing point (IVC) of between 42-46 degrees. The MS3 has an IVC of 51 degrees. That's simply too late. The 113+0 with the 236/242 int/exh lobes. It's a fantastic cam for a 383 where the 4" stroke wants something in the 48-52 degree range. By going with such a late IVC, you can't actually drive your peak HP up to say 6700-6800 where it wants to be, because of the harominic resonance of the intake manifold. It limits peak to 6300 or so. An IVC in the 42-46 range will want to peak in the 6200-6400 range, which is optimized for the intake you're running. When you don't fight that, you make more efficient use of your powerband.
The MS4 is a 239/242 111+2 IIRC. It's a 48.5 degree IVC. So It's actually better, but still not ideal. The issue with the MS4 is it is using LSK lobes on the intake. They will beat the snot out of your valvetrain. If you're looking to go affordable on the intake manifold, heads, etc, then you aren't willing to upgrade the components in the valvetrain to survive those lobes. Lightweight valves, huge pushrods, and very light rockers with springs designed with enough spring pressure to control the valve with that lobe without sabotaging longevity.
I think it'd be better if you take a step back and re-evaluate what you're trying to do. The XE-R lobes on the exhaust of the MS4 and on the int/exh of the MS3 are pretty hellacious on the valvetrain as well, but they can be controlled better and are okay.
I'd much rather you go with something like the BTR Stage 4 with a 235 LSL lobe and 242 XE lobe on a 111+3... That has a 45 degree IVC, better lobes for valvetrain stability, and similar overlap to the MS3/MS4 (so the power output at peak will be pretty much the same). The difference is the BTR Stg4 will make more torque throughout the power band and need less compression to run optimally due to the valve events.
But the thing you're neglecting here is the value events. A 346 LS1 with cathedral port heads and a LS6/FAST intake manifold likes an intake valve closing point (IVC) of between 42-46 degrees. The MS3 has an IVC of 51 degrees. That's simply too late. The 113+0 with the 236/242 int/exh lobes. It's a fantastic cam for a 383 where the 4" stroke wants something in the 48-52 degree range. By going with such a late IVC, you can't actually drive your peak HP up to say 6700-6800 where it wants to be, because of the harominic resonance of the intake manifold. It limits peak to 6300 or so. An IVC in the 42-46 range will want to peak in the 6200-6400 range, which is optimized for the intake you're running. When you don't fight that, you make more efficient use of your powerband.
The MS4 is a 239/242 111+2 IIRC. It's a 48.5 degree IVC. So It's actually better, but still not ideal. The issue with the MS4 is it is using LSK lobes on the intake. They will beat the snot out of your valvetrain. If you're looking to go affordable on the intake manifold, heads, etc, then you aren't willing to upgrade the components in the valvetrain to survive those lobes. Lightweight valves, huge pushrods, and very light rockers with springs designed with enough spring pressure to control the valve with that lobe without sabotaging longevity.
I think it'd be better if you take a step back and re-evaluate what you're trying to do. The XE-R lobes on the exhaust of the MS4 and on the int/exh of the MS3 are pretty hellacious on the valvetrain as well, but they can be controlled better and are okay.
I'd much rather you go with something like the BTR Stage 4 with a 235 LSL lobe and 242 XE lobe on a 111+3... That has a 45 degree IVC, better lobes for valvetrain stability, and similar overlap to the MS3/MS4 (so the power output at peak will be pretty much the same). The difference is the BTR Stg4 will make more torque throughout the power band and need less compression to run optimally due to the valve events.
10-27-2014, 07:20 AM
#23
You'll have to flycut with either if you add milled heads. I flycut. It's not that big of a deal. But the thing you're neglecting here is the value events. A 346 LS1 with cathedral port heads and a LS6/FAST intake manifold likes an intake valve closing point (IVC) of between 42-46 degrees. The MS3 has an IVC of 51 degrees. That's simply too late. The 113+0 with the 236/242 int/exh lobes. It's a fantastic cam for a 383 where the 4" stroke wants something in the 48-52 degree range. By going with such a late IVC, you can't actually drive your peak HP up to say 6700-6800 where it wants to be, because of the harominic resonance of the intake manifold. It limits peak to 6300 or so. An IVC in the 42-46 range will want to peak in the 6200-6400 range, which is optimized for the intake you're running. When you don't fight that, you make more efficient use of your powerband. The MS4 is a 239/242 111+2 IIRC. It's a 48.5 degree IVC. So It's actually better, but still not ideal. The issue with the MS4 is it is using LSK lobes on the intake. They will beat the snot out of your valvetrain. If you're looking to go affordable on the intake manifold, heads, etc, then you aren't willing to upgrade the components in the valvetrain to survive those lobes. Lightweight valves, huge pushrods, and very light rockers with springs designed with enough spring pressure to control the valve with that lobe without sabotaging longevity. I think it'd be better if you take a step back and re-evaluate what you're trying to do. The XE-R lobes on the exhaust of the MS4 and on the int/exh of the MS3 are pretty hellacious on the valvetrain as well, but they can be controlled better and are okay. I'd much rather you go with something like the BTR Stage 4 with a 235 LSL lobe and 242 XE lobe on a 111+3... That has a 45 degree IVC, better lobes for valvetrain stability, and similar overlap to the MS3/MS4 (so the power output at peak will be pretty much the same). The difference is the BTR Stg4 will make more torque throughout the power band and need less compression to run optimally due to the valve events.
But he wants it to make "loapy" sounds like the cars on YouTube.
