543 0R 505

74 duster race car. 3300 with driver. Has SS springs, Competition Engineering Slide a links. Viking double adjustable rear shocks. 29.5 x 10.5 x 15 slicks 4.10 gears 727 with light weight parts. 5000 stall converter. 2 inch headers. Kim
If it were me I'd go the 543, seems like the car set up is a great match. The gearing may keep the rpm low enough as to be a good long lasting engine. I think !