Have 5k mile LT1 GS with Heartbeat 2300 making a safe 575 rwhp right now. If I wanted another 100-150 at the wheels what would I need to be safe and what kind of $ am I looking at? In addition to the engine, are there drivetrain upgrades (axles, eLSD, torque tube etc) that would need shoring up as well? I’m not a fan of meth; would prefer sticking with 93 octane fuel tune.

Contemplating upgrades vs buying something new as I really enjoy the car.

who would be the most credible shops in the Midwest USA that one should consider? Thx

 

This is a bit of a loaded question and you're bound to get a bunch of different answers. As someone who used to own a modified LT1, I can tell you that I did a bunch of research on boosting these engines and what shortcomings are involved in it. First, the ring gaps on the LT1's are not only inconsistent, they are also typically very tight. Heat will be your enemy in this regard and any long pull (highway run, half-mile event) will be rolling the dice. I would highly, highly recommend getting drop-in pistons from a reputable place, such as GPI (Gwatney Performance Innovation) or Vengeance Racing. If you're trying to stick to 93 octane only, you're going to have to get a cam, supplemental fuel (possibly port injection system) and injectors. Talk with the shop you're going through to see what they recommend. If they haven't really built any modern LTx engines then ask a shop that has and build according to their feedback.

As far as the rear end is concerned, it'll all depend on where you're getting traction, how you're getting traction and what the intention of the vehicle is. If you're into drag racing, you may want to consider beefing up the entire back end. Look at possibly getting a Wavetrac diff, stronger axles and torque tube, as you've already mentioned. If you're not trying to drag race, just don't shock load your rear end and it should hold up on that kind of power. Maybe some R888R tires and roll races but, no drag radials or slicks with a hard launch.