LS Engine Swap Question to the Collective

[thepunisher]

I'm stuck, so I figure I'll ask the collective for your opinions as to what everyone thinks. I want to swap the engine in my truck to a modern Gen III or Gen IV motor. The engine must have a manual throttle body because I am going to be using a 200-4R transmission. The two reasons for the 200-4R is I don't have to shorten the drive shaft, and I want stock gauges. I don't want a digital speedometer, and I don't what to run a digital to analog converter to make a electronic transmission work. Besides this would be a unique combination and I like that. I have a target of the engine making 400HP.

Options I have seriously looked at so far;

LQ4 or LQ9 - Good choices, 6.0L, makes good stock HP, from what I can tell the LQ4 should be a manual throttle body, so are the early LQ9's. Motors are a little more expensive and have higher mileage on them. Found one about 200 miles away, 82k miles for $850 for the motor, reasonable prices for the accessories, and computer, little spendy on the engine harness.

LMG or LC9 - Great choice, flex fuel motor, displacement on demand, makes 315 to 320 HP stock, found a complete LMG motor (all accessories, computer, engine wiring harness, exhaust manifolds, 17k miles delivered to a local shop for $1280). Problem is I haven't found a way to convert this to a manual throttle body.

classic Gen III vortec 5300 (not certain in the OPT code) manual throttle body, plenty or motors around which makes them cheap, good choices for after market parts.