Buy a 5K. Run the ACL pistons, you can get 20 40 and 60 thou oversize, although only go bigger if you need to.

 

It'll likely be cheaper this way in the long run, and you can build the motor and then swap it over in a day.

 

You don't need forgies, you'll spend more on the forgies than you will on the engine build.

The block won't need anything else done to it, but if you are doing a full rebuild like that then having everything balanced would be good for longer life.

 

They would balance the crank, front pulley, rods, pistons, flywheel & clutch. It would make life at 6000rpm much smoother.

I'm trying to find a cheap 4k to try this out want to dummy run it on another block before I try it on mine

get rid of your points dizzy go electronic shave the head pull off the fixed engine fan they just waste power the 4k doesnt have lol put a electric thremo fan and a vareble thermo stat switch better exhast is what ive done to mine and give it a good tune and set the timing thats all i have done made a fair diference so much better with out the roar of the engne fan use to shit me :)