valve springs - recommendations

I have a 2002 360 w 4 spd in a 68 valiant sedan. I changed the intake (crosswind) and put on a 750 vac secondary holley carb. I have wore out one set of (rear) tires this summer and had a blast. I was told that valve springs and pushrods were weak. I have not replaced them and continue to beat this thing daily like I stole it. My point is these motors have a nice rumble and make good power with just a intake and carb change. If I was in germany I would drop it in without changing a bunch of crap and go have a lot of fun with it.