I had a real good 340 combo about 14 years ago(that makes me feel old). .060 over with KB243(IIRC) flat top pistons. Good Quench and about 10.4:1 I believe. It had midly ported X heads on it with 2.05 intake valves. I ran a clevlite 298/508 flat tappet hydrualic with rhoads lifters. Mopar M1 single plane with a 700 double pumper. It had hooker 1 5/8 headers with full exhaust out the stock tips. The best ET it ever ran was an 11.98@114 at 3450lbs on a 26x8.5 slick with a 1.63 60ft.

It probably had more in it earlier in its life. It was my daily driver my last year of high school. With stock port X heads and stock converter it went 13.teens@110mph on plain old radials. With the stock converter it didn't even try and spin the tires until about 3500RPM or so. The converter change was responsible for .5 and the head porting responsible for the rest. By the time it ran its best ET it was 4 or 5 years old and had an estimated 30000 miles of high school kid abuse on it and LOTS passes.