New LS to me.
 

First LS I have owned. 8 months ago I bought a trail rig that has an LS 5.3L in it. I have done lots of research the whole rig is so custom everything is really hard to identify. I have been reworking the vehicle some detailed modifications. Motor untouched by me. One of 2 last items up for mods.
I realize now from working on it in detail for the last 8 months I realize the seller did not do any of the work himself on this build. It looks like it was worked on by 2 or three different fairly legit builders, you can see the craftsmanship.
I haven't changed very little on the engine at this point. It feels like maybe 250-270 hp but only drove it a couple times before teardown and rework on the chassis. In the ad the seller posted the engine exactly (LS 327 GM Crate 5.3L Gen 3 Engine with LS6 Manifold reversed block hugger headers) I have only done plug wires re-pluming some fuel stuff changed all of the pulleys. So far I do know it is a 5.3L gen 3 and when I swapped the pulleys i found the original balancer was from a truck because of the spacing. I found that the intake is from a Stock LS2 Maybe, it has 12589181 stamped on the driver side of the intake. From some research I see that this might be a little better then the LS1 stock intake but regardless a small HP gainer anyway. It has full Holley fuel system. Injectors dont know. The TB measures 95mm ish drive by wire. The intake has been flipped 180 deg TB facing out the rear of the motor. I wanted to install a cam, springs and any easy HP gainers maybe to bump it up a little and like i said it feels like roughly feels stockesh 250-270 HP 3?? would be really nice. Im so worried because being new to the LS scene ordering the right parts for the bump. I see there is alot of options to waist time and money. I have been studying the LS for months I realize I'm over my head on this one for small power bump knowledge. I came from the carbureted big block nothing over 450hp. I want to change the cam while in the truck, not pulling the engine just yet but I will later. Oh and this crate was new in 2017 super low hours. Any helpful recommendations would be appreciated.

Welcome!