e.t. guess

Changing my combo on my 68 dart. Now has a 340. 9.85 comp. ported 2.02 j heads. rpm intake. 750 preform dp. Cam is hughes solid 237 and 242 at .050. lift is .534 and .542. 2400 stall and 3.55 rear. New combo will be same motor except mopar 557 cam and eddy street tunnel ram with two small avs carbs. Converter will be 3600 stall and rear is 3.91. on 26in. drag radials. Cars has headers and 2.5in. exhaust. My best with my current combo is 12.94 at 106 and 1.94 60ft. Think I can get low 12s. or high 11s.