K10 vs K20 - a few questions:

[mrein3]

Besides HEI cap clearance, the biggest advantage I see to leaving the t-case in its spot and moving the engine forward is stuff happens. And by stuff happens I mean stuff breaks.

If you put in a 700r4 and leave the engine in its spot, thus modifying driveshafts, you're no longer looking for stock pieces when you break a front or rear shaft. (I know they usually don't "break" but u joints freeze, the front shaft no longer moves in and out due to lack of maintenance, etc).

If your 700r4 goes out and you're down on your luck, you can just re-install your th350 and put the engine back to where it was.

I don't mean any disrespect to anybody but in my opinion the more stock pieces you use the better and easier chance you have down the road of fixing stuff.

Another thing to consider, and I don't know if its possible, would be to install a gear vendors OD unit behind the transfer case. Think about it. I don't know what you possibly would need OD for when you also need four wheel drive. The only time I get out of 1st gear in my th350 when I'm in four is when I'm driving across the lake and then I never get to 3rd. Then when you're in camper mode and driving down the nice dry slab you have the t-case in 2 and the lock outs not engaged then you could start using the OD.

Personally I would just go with a 700r4.