How to build a 13 second 340 Duster

Back in 1978 I built this 340 Dart Sport for my buddy. It was a 1970 340 I rebuilt to stock specs and did a nice 3 angle valve job with stock valves. No porting at all but I milled the heads to get a true 10.5 comp. I used all the stock valvetrain but added a MP .474-280 cam. It had 1-5/8 headers and I used the stock electronic dist and recurved it. Had a LD-318 intake with a 650 DP. Rear was an 8-1/4 with 4.10's and G/60 street tires as we did not have drag radials in the 70's. I also had a stock 904 and convertor from a 318 Dart. The car would spin the tires bad so I had to walk it out without spinning the tires and ran 13.49 @ 105. Yes thats 105 mph which is easy 12.80's on a good sticky tires. It was a basically stock 340 with the MP .474 cam and some bolt on's. 340's run hard and like was said a good basic mild 340 combo will tap the high 12's with a good fine tune using headers with the right convertor and gears. Good luck with your combo. Ron