S/C 10-20lb 302-331 c.i.d. Best for 6200-6500 rpm. Great with TFS or Edelbrock heads Minimum 42lb injectors and 80mm mass air. Recommended 3.73 to 4.10 gears, good drivability down to 2100 rpm, mild idle, rpm range 2500-6500, needs 2700-2900 converter.