who all has swapped in a LS1?- need motor mount info

[68c10owner]

I`m picking up my GEN III LS1 truck motor on Monday. I`m putting it in my 68 swb. I know I need adapter brackets but can I use the stock sbc frame mounts and stock motor mounts? I was told "it would probably work" but haven`t found out for sure. What is the best way to mount it and what about headers? Here is a little info on the motor. I don`t know the year yet or the mileage but it`s a pretty complete 4.8 but I`ve already bought a 5.3 crank and rods to turn it into a 5.3. It`s missing the a/c compressor,alt., pwr steering pump,starter and computer and harness. It has the acc. brackets though. It also has 2 cracked heads so I`ll need to find a set eventually. I`m not worried about the computer because I need to have it built to my specs anyway. I`ve already emailed Speartech about building a computer and harness. Anyway, any help that you can offer would be great. i know there are a few guys here who have done the swap so I`m hopeing these people chime in and post. Thanks.