I actually like the 400 chevy blocks. They make a great high torque drag engine, The "Siamese' cylinder arrangement actually lends it to heavy abuse without to many issued. I CURRENTLY HAVE five 400'S. The next one will be for my40 Dodge ratrod drag truck. Some key issues with the 400 block is to use main cap studs, instead of bolts, Also use a stud instead of a bolt to attach the oil pump. Because of the larger main journal diameter, the rear main cap is weak and by using a bolt to tighten down the oil pump it can distort the cap making for a failure point. I had a 400 destroked to 352 by using spacer bearings and a forged large Journal 327 crank and 6.125 rods with custom 400 flat top pistons, solid lifter 270 cam. Felt like a grocery getter until it hit about 3500 RPM, then you better get ready to shift cause the tach stood on 8000-8500 through every gear. Really Quick winder. Big bore /short 3.25 stroke was a wicked combination! It felt like the powerband on a two-stroke dirt bike. I use a good radiator, drill the heads for steam holes using a head gasket as a template and always use head studs on a 400. It almost elimnates blown head gaskets. Because of the increased 1/8 bore, it really increases the breathing potential when using 1.94 and 1.5 valves the small valves keep air/fuel mixture velocity high. this design also unshrouds the valves for better breathing. These engines really respond well to a 750 mech secondary or slightly bigger carb. these make a great street rod engine or a Drag engine.