My 73 Duster was originally a 6 cyl car but now has a 360 mated to a 727. I believe the trans to be mostly stock but the engine has the Edelbrock performer carb (1406), cam and intake. It also has roller rockers and ceramic coated headers along with the J heads. I just switched out the 2.93 gears for some 4.10's and when standing on it in Drive I notice it start to lay down in 3rd gear around 4500 rpm. It doesn't feel like it's out of gas, but it stops pulling and you can feel it just sort...
Fuel Starvation?
