... but if I start on this project, it will never end. Then there is always the "should have just got a 3/4 ton Suburban with the diesel already in it"... but that's pretty rare to find.
Your right it would be much smarter to find a 3/4, 6.5 engine truck. You will need to swap out everything to include the fuel tank if it has the same one as your truck, the fuel lines, feed and return, wiring harness, electronic foot feed(gas pedal) install a PMD relocating kit or a manual injection pump, replace the factory lift pump with something more reliable, install dual batteries, oil cooler with new lines to fix the leak prone factory ones, oil filter relocation kit to fix the leaky factory 90deg mount, most likely replace the oil pressure sending unit that fails due to crappy engineering and since you will have it out go ahead and replace the injectors, timing chain with a gear drive the exhaust crossover and down pipe.
Now after all that you will have a very reliable but only slightly more powerful engine that everyone will knock every chance they get. I know all this because I have an even more rare truck; a 94 Blazer with a factory 6.5 with a 4l80E trans. I love the truck and engine but would never think about swapping one into a former gas truck. The 6.5 never was and never will be a powerhouse diesel. When stressed to it's limits, which aren't far off from stock, they can let go in a lot of different ways. But when left near stock they are very reliable after a few easy fixes.
As for the 6bt, great engine and a whole lot more torque than a 6.5 or 5.7. But it will require a SAS in order to support all that weight.
I like the look of your 'burb and you seem to enjoy it. I say keep the gas and go for a mild RV cam, long tube headers, and a new intake manifold to up your torque to where you want it. Just my .02.
Happy adventuring.:victory: