one thing leads to another

[wibilly]

i wqas telling a buddy i was gonna change the rear end in my truck. i have 3.73 thinking about going to 3.07's to save a little fuel. i drive my 69 350 4 speed truck 30 highway miles a day to and from work. then he offers up a 72 chyanne super thats been sitting in his pasture as long as iv'e known him. it was restored 10 plus years ago 2 owners ago and driven very little since. had all new suspension and brakes then and has a 3.07 posi. he says just do a body swap. i'm thinkin ok. i don't wanna be without my daily for long but do have several other rides. so i start thinking about this over the last week you know get the frame ready then do it one weekend. then i'm thinking about the crosmember swap and this and that, not gonna happen in a weekend. then today i think about that 500 caddy moter and 400 stashed out back.you see where this is going right? now i'm thinking back to the miliage thing that started all this. am i gonna gain anythig or should i just keep the 500 for the c/20 it gonna go in way down the road?