Keep it #'s matching or swap?
 

Have a stock 307 in my 70, should I leave it in there and make it just a little more powerful and keep the car #'s matching or replace it with a 350 but keep the 307? I keep hearing not to waste my money or time on the 307 I'm definitely taking the powerglide out and putting a 3 speed in since i'm using it as a daily driver. What's everyone opinions?

Put the 307 in the corner of the garage. Build a nice 350 for it. If you ever sell, let the new owner have the 307 to put back in it if he wants.

What Tony said, if you have the room to store the 307. Otherwise just get rid of the 307. Number's matching is important, sometimes but not always. If it was a true SS with documentation it would be important. Number's are important to Vette guys too but it's not that big a deal on a plain Jane Malibu,

Gotcha, that's kind of what I was thinking. Just never had anything number's matching so didn't want to just yank it out and alter the set up. I know the 307 isn't anything to brag about and wanted to go with an LS setup

Don't keep the 307, scrap it. The world will be a better place with one less 307. :)

Do what makes you happy. I'd say instead of a 3 speed do some research on a 700R since it's going to be your daily driver....nothing like that overdrive.

Why not just freshen up the 307 if your not building a hotrod and just using it for a driver?

What's a chevelle without some power? Hate to dump money into the little engine that wishes it could and not be satisfied with the outcome where as I know I would be pleased with that same money into a better power plant (i.e. 350, ls1, etc.). Found a good ls longblock for 300, so after I rebuild the suspension that's the direction I'm going.

Good luck, keep us posted on your progress.