273 Stroker, 4.00" Crank

I'm thinking you'd likely have to notch the bottom of the bores for the rods. Probably even with the thinnest rod beams available.

Nobody makes any pistons so they'd have to be custom as well. The cost would be prohibitive I'm sure.

The other thing is...all that work and you get a 336ci engine (at +0.030). Bore size is very small so you won't get very good airflow. You're probably better off overall with a stock stroke 318. Even a 318 block with the same exact crank will make a 390ci engine.

For performance, the 273 is a boat anchor - especially when 318s are almost free and look identical on the outside.