273 piston options

I’d like to say 7k but as high as the stock stuff that’s going in it will allow - for now.
If I buys pistons that fit the stock rods then that’s what’s going in it now.
I’ll be using the stock rockers and flat tappet lifters for now.
I’ve got a set of solid roller lifters but I’m thinking solid flat tappet for starters. I dount think that will be the limiting factor just yet.
I’ll be doing oiling mods and Adding a stiffer spring to the Melling 72HV pump I found in the engine when I took it apart.
This is going to be a fun project for me, not a race engine. If the parts I choose limit me to 6k then that’s what the limit will be. Until I decide to buy a better crank and rods. Or springs and rockers if that’s what’s limiting me.
Short version: I’m aiming for 7k.

At 7k, if you keep your tune up in check you shouldn’t have any issues. The stock crank and rods will take 7k all day long. Just make sure you have good rod bolts.