I scrounged through HP tuner's website and found my answer. For those interested, the 0411 PCM can run with speed density. Supposedly the 98-99 LS1 engine file runs a speed density availability alongside a 24X set-up. I'll download that file once I purchase the HP tuners dongle ect. To run speed density I'll need to disable the MAF codes and upload the 3 bar MAP sensor file and install a 0-5V GM MAP sensor.
I'm going to do some research and see if the AEM 3 BAR MAP sensor will linearly output the same voltages. I've seen a bunch of failures in the DSM community on the GM 3 bar sensors and I want to avoid that if possible.
I have a marine intake manifold but I'm also interested in installing a ramjet intake as well. I'm curious if they make a larger throttle body for it though as my current throttle body on my whipple set-up appears to be larger in size than the ramjet set-up. It may also be easier to complete the swap with sticking to the marine intake though. I'm only interested in the ramjet as it looks to be more of an efficient piece than the marine intake. I know these swaps have been done many times but they're isn't much hard info on both sides for pros and cons of each to plan out my next move.
After I install the 0411 PCM I'll see if I can raise the RPM limiter to 6K and see how the truck reacts. Once I install the 24x reluctor wheel I'll then install a GM LT1 hotcam or a higher duration cam for a big turbo build. This truck will not be used to tow so I'm not worried about that effort anymore. I'm looking to go down this path of modifying the L31 platform to maximize it's performance and overcome the challenges of the original design. I do understand that ease of swapping in an LS platform and I respect it's capabilities as I've done a few in the past but nothing is more interesting to me than seeing something like this in the engine bay.
End goal will be a forged 383 stroker, aluminum vortec heads, some type of intake and big rear mounted turbo for 20+psi of boost. The truck is more of a show piece to lure more business my way for performance modifications and engine building. The area I live in is littered with military guys and retirees looking to go fast and finish their dream rides. The better I'm able to show my skill set the more success I'll have in advertising myself at local car meets and performance shops.