1990Z71Swede
I'm Awesome
Well since I have real life experience with both the LC9 an the L05 I might just as well chip in.
These are two VERY VERY different beasts, the LC9 is a fun little screamer, and paired with a Suburban and a 4L60e its is like having a race motor trying to pull a freight train. It works pretty good but it needs revs, and is not particularly fast... and that two gear 75%WOT downshift is going to make people think your an idiot sometimes.
The LO5 on the other hand is a low RPM laid back workhorse with powerband somewhat like a modern turbodiesel, that is also the only thing modern about it The difference in powerband is night and day, when the LC9 is starting to pull the LO5 is shifting into next gear.
To make an LC9 work well in an OBS you most definitely need the gearbox that came with it or atleast try to match its calibration of shift points and lockup release. 3.73 gears or maybe even 4.10 is probably very helpful also. Anything less is likely going to be putting that little screamer out of its powerband most of the time.
AFM has to go, when it works it works and it does save quite a bit o fuel under low load conditions. But "all" that savings is a total wash when/if it craps out. Choose something mild camshaft-wise if you like to tow stuff. Also take a careful look at the cam bearings and educate yourself on the O-ring issues in the path from oil pump pickup to the oil filter.
The LC9 is suuper smooth running, the LO5 is not as smooth, the older technology shows, but once warmed up it is pretty nice too.
ANY of the first gen SBC build combos suitable for a truck is VERY likely to have more low RPM torque than a comparable LS based motor. If you follow up with proper gearing and gearbox calibration that is not necessarily a problem though, but if you don't, your truck could very well be slower and less fun with the LS.
If I where to build an LS OBS I would be looking into an LQ9, 4l80E, 14bolt SF 4.10 combo.
These are two VERY VERY different beasts, the LC9 is a fun little screamer, and paired with a Suburban and a 4L60e its is like having a race motor trying to pull a freight train. It works pretty good but it needs revs, and is not particularly fast... and that two gear 75%WOT downshift is going to make people think your an idiot sometimes.
The LO5 on the other hand is a low RPM laid back workhorse with powerband somewhat like a modern turbodiesel, that is also the only thing modern about it The difference in powerband is night and day, when the LC9 is starting to pull the LO5 is shifting into next gear.
To make an LC9 work well in an OBS you most definitely need the gearbox that came with it or atleast try to match its calibration of shift points and lockup release. 3.73 gears or maybe even 4.10 is probably very helpful also. Anything less is likely going to be putting that little screamer out of its powerband most of the time.
AFM has to go, when it works it works and it does save quite a bit o fuel under low load conditions. But "all" that savings is a total wash when/if it craps out. Choose something mild camshaft-wise if you like to tow stuff. Also take a careful look at the cam bearings and educate yourself on the O-ring issues in the path from oil pump pickup to the oil filter.
The LC9 is suuper smooth running, the LO5 is not as smooth, the older technology shows, but once warmed up it is pretty nice too.
ANY of the first gen SBC build combos suitable for a truck is VERY likely to have more low RPM torque than a comparable LS based motor. If you follow up with proper gearing and gearbox calibration that is not necessarily a problem though, but if you don't, your truck could very well be slower and less fun with the LS.
If I where to build an LS OBS I would be looking into an LQ9, 4l80E, 14bolt SF 4.10 combo.
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