Even for a Chevy, 132K is a lot of miles. Did you run a compression check or leakdown test? I'd be inclined to pull the heads and do a valve job at least. Then you can check the bores and decide if it needs rings, too.
Performance? There's a ton of stuff out there. Given it's a 1974, you probably have low-compression heads (for smog) so either different heads or different pistons are an option. And get a cam designed for towing, etc.
Just my two cents' worth....

George
'53 3600