I am not a fan of the 317 chambers. Terrible quench effect, especially with the LQ4s terrible chamber design. I have put 243s on a LQ9 and it would still run well on 87 octane but really woke up on 93 octane. My LQ9 had pistons 0.005" above the deck and I used the GM MLS gaskets that are like 0.051" thick. On the LQ4 I went with LE ported and 0.020" milled 862s with 2.00" intake valves.

 

75k miles?! That truck is barely broken into, LOL.

Seriously, a lot of these trucks routinely go 300k+ WITH a landscape or construction trailer behind them 100% of the time. My mason has one and I don't even know how many miles he's got on it. I don't think I've ever seen his truck without the trailer behind it.

I've bought an 06 Suburban LQ4 2500 a few years ago with 225k. It's now got 265k and original drivetrain as far as I can tell. Last spring it had developed an intermittent lifter tick, so I pulled the engine to do a freshen up. Bearings and cylinder walls looked really good. New bearings, new lifters, light cylinder hone and piston rings and it's back in action. I went with the Summit 8718R1 cam and I really like it.

With 75k, I would absolutely not even mess with the transmission. Just do a fluid change. If look around here, the Transgo kit is not even something the transmission performance builders recommend...Cam and headers and let her rip.

 

What are everyone’s thoughts on tuning this combo?
Is there away to do an 87 tune and a 93 tune on like a tuner?

 

Spend $1000+ doing engine upgrades and what not then neuter it on 87 octane makes ZERO sense to me. I tune everything for 91 octane. The fuel mileage improves enough to equal the added fuel cost on everything I had tuned to run on 91. I have had bone stock vehicles with a lot of knock retard on the stock tuning running on 87 wake up on 91 especially with a good tune.

Even my stock L31 350 responded like I was spraying it with a small shot of nitrous on 91 with a good tune. That one went from 185 whp and 250 wtq on the stock tune on 87 to 257whp and 330 wtq with tri-y headers and a good tune on 91. It made 229 whp and 304 wtq tune only.

 

I have a similar truck with 799 heads, 1 3/4 headers, flat top pistons, summit 8720R1 cam
honestly big truck torqunator or btr truck Norris will give you more power and torque and be amazing. Even with the cam I have the torque gains start right at 2500rpm which is the factory convertor stall (2600rpm ish)
I'm running 10.6:1 comp after calculations and softening the heads slightly. I also coated everything with a ceramic heat coat to prevent heat soak on the chamber and Piston.
you could probably get away with 10.1 (799 heads on lq4 dished pistons) with 87 but it will pull timing when towing, but a little 93 and you'll probably pull nothing when towing.
I was worried about comp ratio but the guy I bought heads of off had a 10.7:1 truck running 87 although a lighter 1500
​​​​​if your looking for more torque in cruising rpm of 1800-3000rpm you'll want a smaller cam and I'd probably go the Summit route to save money. the truck Norris gains are a bit higher. also realize the summit cams can be noisy because they are really getting all the power they can and have quite aggressive lobes which will help hold power longer and also alow it lower.
you would need your own copy of HP tuners to change tunes all the time best bet, set up the tow haul mode good to keep the engine reved up a little which will lessen the effect the trailer has. if your tunned well with good low and high spark tables knock learning may be able to adjust well enough for towing. realize that even factory these trucks pull a ton of timing 87 without a trailer from the logs I had taken on the stock motor