The main difference is that there is an open area under the plenum chamber. Crosswind 53025. new polished aluminum dual plane Air Gap intake for big block Chevy engines. For use with '66-'00 396, 402, 427, and 454s with oval port heads.
Complete Aluminum Cylinder Heads BBC Chevy 454 320cc 115cc 2.25/1.88
For GM Ford SBC BBC Chevy 350 Polished Aluminum Alternator Pulley Fan Blade
Polished Aluminum 1 Groove Short Water Pump Pulley Suits Chevy BBC 396 454
SBC BBC CHEVY POLISHED ALUMINUM STRAIGHT UP WATER NECK 283 327 350 454 502 #6002
Chevy BBC 454 Polished Aluminum Serpentine Engine Pulley & Short Water Pump Kit
For SBC BBC Chevy 327 350 454 90° Polished Swivel Water Neck Thermostat Housing