My car has not cost me a lot, I think about $4500 so far and it is a driver. Safe and mechanically sound. The only non car part I think I have on it are the door panels which are plastic shower stall walls. I guess the Rustoleum paint counts also.
I think rats are still popular but for me I drive mine and am not into the lawn chair car shows. I go to them but do not enter my car in them and I think quite a few around here do the same.
The 700 is cheaper. Adapter plates aren't too spendy. One good thing about an Olds 350 is a larger bore than Chevy 350 and they are tough. Also a 455 Olds is pretty much a bolt in swap if you decide to upgrade later. Good luck, my Olds 350 surprised many people.
Mine was a 1971 Buick GS 350 with an auto. I found out why it shuddered at 115 mph as it threw a rod and locked up the rear tires at that speed. Fun ride!