Entire table.

 

That's stock. Zero that yellow orange rectangle area. See how it likes it.

 

@jeepin Jeff what cam did your swap guy recommend?

Like @68Formula recommemded, i like the 8727. The 8728 might be a little too big. I found these descriptions.

SUM-8727R1 Truck Torkinator, 200 int. / 205 exh. 113 LSA+ 4 adv. .550 int. / .550 exh., -9 I/O, 29 I/C, 40 E/O, -14 E/C, -23 overlap. Note this intake closing point is 29 abdc a full four degrees eariler than SUM-8718R1. This wll shift the powerband down even further BUT with .050 extra lift, that's going to help through the range and keep it still fairly strong all the way to 6k rpm. It's designed for use with our SUM-174002 LS6 springs.

SUM-8728R1Big Truck Torkinator, 212 int. / 218 exh. 110 LSA +3 adv. .600 int. / .585 exh., -1 I/O, 33 I/C, 42 E/O, -4 E/C, -5 overlap. This thing is all attitude. It's for the guy looking for a True tow cam with 33 abdc intake closing, but also wants a bit of an idle to it AND we've pushed this to .600 lift. This cam has more torque and power production than anything else we've seen on the market. The truck lobes are designed for long spring and valvetrain life and our new SUM-174004 .600 lift beehive springs are the perfect match! This would make an excellent turbo cam with 4.8 for instance. Also good for a turbo car where the owner is looking for good streetability and wants to retain the stock stall converter

 

Does “overheating on long grades” in this context mean “overheating over 5000 feet under heavy load”? The air is thin up there, and doesn’t cool as well.

 

OP,

You've received some stellar advice from the community. We'd love to sell you XYZ Bumpstick but we don't think that's the fix. We're liking what @68Formula and @grubinski have suggested. Ignition timing and elevation.

Here's a statement from you that also leads us in that direction.

It seems like we're dealing with an engine that is under heavy load, experiencing retarded timing, and operating at high elevation.

Based on some calculations, at 40mph in 3rd gear (1.532) with a 35" tire and 4.10 gears, the engine would be running at approximately 2,411 rpm. Considering the input from 68Formula and the timing log showing retarded timing below 4,000rpm, as well as our mountain climb, it's coming together why the engine feels sluggish and is overheating. It would be helpful to have a log of everything else in this scenario. We suspect that the engine is running lean and likely experiencing some knocking under load as it struggles up the mountain, which could be contributing to the overheating issue.

Considering this, you may need two different tunes: one for everyday driving and another specifically for climbing mountains. We also think that @LS1 TJ's suspicion regarding the temperature at which the fans come on could be helpful to consider. It's fine during everyday driving; however, when mountain climbing, it might be better for them to kick on at a temperature 10-20 degrees cooler.

It's nice to see the community coming together and providing assistance. That's what forums like LS1Tech are designed for: like-minded folks coming together, sharing ideas, and helping each other out when in need