383 Stroker?

A Reworked 440 Forged Steel Crank & "ly" 440 Rods can be used in a 383 Block to make a "438" Cubic Inch Engine.
Aftermarket Pistons are available for the 438 build.

Pretty easy 500hp "no brainer" type build, even with the 440 Source "Stealth" Heads and a very driveable Flat Tappett Hydraulic Cam.

Exhaust manifolds WILL lower the power substantially, but I have never tried them on the Dyno, to know how much for sure ?

If you purchase a 440 Source Kit, make sure you have it checked THOROUGHLY, by a qualified Automotive Machinist BEFORE you assemble it.
Most are fine, some are NOT !