I’m not sure which combo the “543” is.

4.375 x 4.500 is 541.2
4.380 x 4.500 is 542.4
4.500 x 4.250 is 540.7
4.440 x 4.375 is 541.9

68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads