Original 307 engine, do I keep it in or get rid of it?

[Scottk6204]

Hey guys, I recently bought a clean 68 short box that has its original 307 3 speed column in it. I have already purchased a 5.3 Ls motor and 4L60E trans for it and was wanting to get that put in. My problem is this 307 runs like a top and to get this 5.3 installed is going to cost me another $2000 after extra parts and labor. There is a lot of other things I would like to get done on my truck and will not be able to do that if I spend my money getting this engine swap done.
So do I sell this 5.3 set up and not be so buried in this truck money wise or do I just go ahead with my original plan?