Everything has been installed and looks great. The engine is a 3500 Express van 6.0L from an '03 with fairly low miles (~50K, looks great, well taken care of). Backed by an LS1 T56 with some upgrades...

A few questions on the tuning...

I did make some minor changes to the engine along the way. Most notably, the throttle body is an 85mm TB from Pro Products, since the JY took that off before they gave me the engine. Also, it's got shorty coated headers (1.5" primaries, 2.5" collectors), and full dual 2.5" mandrel bent exhaust, with H-pipe and cats. Also has electric fans VS the stock engine-driven. Corvette accessories but the A/C is not hooked up yet.

The intake is rather short, being a 90 degree reducing elbow from the MAF to the throttle body and about a 12" section of 3.5" straight pipe from the filter to the MAF. The filter is an Airaid filter from the old CAI in the S10 (was a 4.3).

Now, I'm trying to run this all with the '411 PCM, so I was trying to accomplish everything with an '02 Silverado 6.0L base tune. I did take a look at an available '04 Express van base (all that was on Holden Crazy), and noticed a lot of differences in the tunes. However, it's a 1Mb tune and won't fit on the 512Kb PCM, and the newer PCM won't drive my gauges.

OK, questions...

Stock throttle body size? If the 85mm TB is going to give me a lot of problems and not much gain, I'd rather go find a stocker and throw on there than mess with a lot of tuning.

With the '02 tune on there, the truck will idle ~so-so and drive, but does not do so well enough to be reliable. Doesn't have as much power as expected, either.

Also, what would cause the truck to stay revved over 3k rpm for long periods of time? Well, besides a lead foot... It doesn't feel good enough to drive below say 1800 RPM so I tried to stay above 2k or so on the initial test drive, but once you get it above 3-4k it will "hang" - foot completely off the throttle and it will stay there for 6-8 seconds before falling off to idle. Near the end I figured out I could help the issue along by double clutching - once to shift to neutral and another push of the clutch pedal would cause the RPM to fall...

Anyways, sorry for the long post, and I do appreciate any help.