Aha. Yes a 509 is too hot, I wouldn't use it unless you had maybe another 30-40 CI to fall back on.

If it's going to get eddy heads, then something close in specs of an MP .528 and an RPM intake will do what you're looking for. If you'd rather have a hydraulic, be careful with lobe separation and try to find something in the
112-115 range...but the solid will almost always run better all the way around.

For pistons you're looking for 1.32 compression height and 4.375 bore, flat top with valve reliefs. When the machine work is done you will want anywhere from zero deck to around .008" in the hole which will give you around 10.5 to 10.75:1 with most off the shelf composition gaskets. You won't really "need" forged pistons for this unless you think you might get greedy for more power later on, but forged is not much more than hyper/cast, and it's a worthwhile upgrade for later on. It also adds value to the engine in case you decide to sell it later.

It will live forever with properly prepped LY or 6 pack rods....but once you're done with rod prep, you're usually $200 away from aftermarket H beams, so I'd recommend a budget H beam rod like Eagle, or something similar.

The above build is tried and true, a local buddy has it in an E body with a 6 pack intake and TTI headers and he has a blast with it....AndyF also wrote a mag article about the same build some time back....it flat out works.