If you really want a nice little RPM loving package try a 4.125 bore with a 3.25 stroke. It yields 348 cu. in
From waaay back, but I dig that deal. I have a 3.26 stroke billet piece with intentions for a 400 based mill, +.040 for 355 CI. You know, grab a gear and wring it through some RPM on the way to church.
Buddy shop owner down the road runs a 377 in his camaro. No joke. It flat out rips with 1/4 mi times high 9's all motor. RPM KILLS, so keep that in mind. I personally like the 3.875 combo, always made plenty of TQ/HP for me, no matter. You can get a 3.48 stroke crank with the 400 main size and LJ or SJ rod, whatever you want. You need to come up with a specific goal for this motor, figure out how much track time and how much street time and go from there. Gears tire size trans weight heads cam intake etc etc etc. I'm looking at 10 400 mained 4340 cranks with strokes from 3.3, 3.35, 3.4, 3.48, 3.5, 3.562, 3.625 and 3.875 available for 5.7 or 6.0 rods. You can build your 400 beast into a variety of c.i. with more head options than you'll care to look at too. It's all in the COMBO, and it all works together... when you get it right. JMO One more thing you might consider, that being how much HP you make in the stock block. I've seen them over 700HP on motor but that's a crap shoot not to grenade. I've run them with 500+ and hit 'em with a 150-200 shot without trouble. All I'm going to add is to run it with a solid flat cam so it makes some noise.