NewbVetteGuy
Well-Known Member
As we know the SMOG ERA SBCs are plagued with both terribly restrictive exhaust systems AND terrible static and dynamic compressions (and not very great head flow).
One of the first performance improvements that I think rightfully gets recommended, is to address the exhaust system. A good, high-velocity header, 2 1/2" dual exhaust, and good flowing mufflers are all plentifully available for most platforms.
IMO, this opens up a HUGE opportunity, even for the guy on a budget who doesn't want to buy new aluminum heads, fancy valve train parts, and a roller cam upgrade, to simply move to a tight LSA, low duration cam, with way more modern lobe designs than the OEM cams that were mostly designed in the 50s.
Dramatically better dynamic compression, mid-range torque, and even maybe some good sounding cam chop from the overlap that's now a positive thing with the good exhaust.
BUT... There's some seriously slim pickings out there when it comes to both low duration and tight LSA SBC Flat Tappet cams. So I'm hoping we can get a decent list of options identified in this thread.
I know @grumpyvette @Grumpy is all about the Crane cam catalog (which I know nearly nothing about).
I think the Isky Mega cams were pretty much made to fulfill this niche (at least the 262 and 264 Mega cams are on a 108 LSA; the 256 Mega, randomly moves to a 112 LSA). -Isky 201256-262 is a split duration option that seems reasonable but on a 110 LSA... Mega 262 has 46 deg of overlap. Mega 264 -48 deg overlap
I've heard the CompCams CS252AH-8 (212/218 @ .050", 108 LSA) and the CS260AH-8 are also good options here, but they seem like special order cams I don't seem them carried by Summit or anyone else, for that matter.
Spring upgrades seem mandatory for all these options, which, I personally think is well worth it.
The Lunati Voodoo 256 on a 108 or 109 LSA I think could be great for this purpose if you got the ICL right but I haven't looked at where the exhaust open and close would be then. I'm pretty sure the exhaust events would be better than the Thumper cams still...
Voodoo 256:
256/262 adv, 213/219 @ .050", .468"/.489" ->LSA 112 108 ICL as the standard grind specs
If moved to a 109 LSA it would have 41 deg overlap; 43 deg overlap on a 108 LSA.
-The split duration, with a good exhaust system would give up some torque, but then run better upstairs with the shortish durations and tight LSA, right? Seems like it could be a good trade-off for some people, in my thinking.
What other good options are out there for this kind of application?
Are there other cams that could be ground on a tighter LSA and work well?
(I haven't, but want to look at Comp High Energy or Magnum lobe options because comp will grind on any LSA without an upcharge...)
Adam
One of the first performance improvements that I think rightfully gets recommended, is to address the exhaust system. A good, high-velocity header, 2 1/2" dual exhaust, and good flowing mufflers are all plentifully available for most platforms.
IMO, this opens up a HUGE opportunity, even for the guy on a budget who doesn't want to buy new aluminum heads, fancy valve train parts, and a roller cam upgrade, to simply move to a tight LSA, low duration cam, with way more modern lobe designs than the OEM cams that were mostly designed in the 50s.
Dramatically better dynamic compression, mid-range torque, and even maybe some good sounding cam chop from the overlap that's now a positive thing with the good exhaust.
BUT... There's some seriously slim pickings out there when it comes to both low duration and tight LSA SBC Flat Tappet cams. So I'm hoping we can get a decent list of options identified in this thread.
I know @grumpyvette @Grumpy is all about the Crane cam catalog (which I know nearly nothing about).
I think the Isky Mega cams were pretty much made to fulfill this niche (at least the 262 and 264 Mega cams are on a 108 LSA; the 256 Mega, randomly moves to a 112 LSA). -Isky 201256-262 is a split duration option that seems reasonable but on a 110 LSA... Mega 262 has 46 deg of overlap. Mega 264 -48 deg overlap
I've heard the CompCams CS252AH-8 (212/218 @ .050", 108 LSA) and the CS260AH-8 are also good options here, but they seem like special order cams I don't seem them carried by Summit or anyone else, for that matter.
Spring upgrades seem mandatory for all these options, which, I personally think is well worth it.
The Lunati Voodoo 256 on a 108 or 109 LSA I think could be great for this purpose if you got the ICL right but I haven't looked at where the exhaust open and close would be then. I'm pretty sure the exhaust events would be better than the Thumper cams still...
Voodoo 256:
256/262 adv, 213/219 @ .050", .468"/.489" ->LSA 112 108 ICL as the standard grind specs
If moved to a 109 LSA it would have 41 deg overlap; 43 deg overlap on a 108 LSA.
-The split duration, with a good exhaust system would give up some torque, but then run better upstairs with the shortish durations and tight LSA, right? Seems like it could be a good trade-off for some people, in my thinking.
What other good options are out there for this kind of application?
Are there other cams that could be ground on a tighter LSA and work well?
(I haven't, but want to look at Comp High Energy or Magnum lobe options because comp will grind on any LSA without an upcharge...)
Adam
