●⬤Oil pump primer tool Compatible with all small and big blocks including popular sizes of 283 307 327 350 396 400 402 427 434 454; SB/BB Chevy V8 & Chevy V6 Engines. ●⬤ Oil Pump Primer Primes the lubricating system of a rebuilt engine prior to its first start to prevent the damage of a dry start. ●⬤ Oil primer tool works by connecting to the oil pump shaft through the distributor hole and inserting it in an oil pump. ●⬤ SBC engine oil priming tool: Thick shaft design with triangle shaped end for no slippage. Use with 3/8" or 1/2" chuck hand drill ●⬤ Engine oil primer: Thick shaft design with triangle shaped end for no slippage. Use with 3/8" or 1/2" chuck hand drill.