555 BBC Shortblock. Dart 9.8 Big M block with billet steel caps, 4.560 bore, stainless o-ringed, hard blok filled to bottom of water pump holes, JE 18 degree gas ported pro mod pistons with thermal coating, Eagle 6.535 H beam rods with L19 bolts, Scat 4340 Forged 4.250 stroke crank, Total Seal Max Seal Gapless top ring set. ATI Super Balancer. Completely internally balanced by TRE Racing Engines. Only 8 1/4 mile shakedown runs on shortblock. No nitrous use. Good for big horsepower. Went to 708 BBC and don't need this shortblock. You can put on a set of Big Duke or Big Chief Heads and make 1300 HP without nitrous. Spray it for even more HP!! Asking $5900 or best reasonable offer. Ready to run!!