Let me screw up your day completely with starting research over. The 377 chebbie??? Look into and ask around to hear other thoughts about building a 377.
Allows you to build around a forged crank VS the cast option of the 383, yes you can spend $$ for aftermarket crank but most do not. Allows use of GM hot rod or performance rods but aftermarket are about as cheap when doing all the right reworks of rebuilding stock rods properly. Allows non -Siamesed cylinders on 5-7 and 4-6. (with 350 block only) Allows tons of head selection and no ?? about steam holes or not and more options for head gaskets.
Downside = Uses smaller crank - rod diameter but with todays oil and oiling mods not sure it is a big deal but it is a ?? You do loose a few cubic inches from 383 to 377?? Does require block clearance grinding and heavy metal in crank but so does the 383 so a wash I think. Less popular build so piston selection is .
SPECIFICATIONS. Bore: 4.125. Rod Length: 6. or at least 1 way to get there.