I have a dilema and a decision I need help with...

[Crispyr1]

So I have a 68 SWB C-10 without posi. I have PB, PS, Disc brakes all around. So stopping isn't an issue. I have a 400sbc that is tuned port injected but my 700R4 just went out. I originally wanted fuel injection because I wanted it to be as close to a daily driver as possible. I got the raw end of the deal with a mechanic and the tuned ported 400 is what I got. Don't get me wrong I love the 400 but it doesn't give me the functionality I need. So I was thinking of going with the LS1... any thoughts? Has anyone done this, that could tell me the pro's and con's of the swap, Headaches, and what to expect? I hate having to wait for my truck to warm up and the fuel economy is super bad, will the LS1 be any better? Your thoughts and opinions are appreciated. TIA!!!