It's been a long time but when I dropped a FE (64 427 ) in my 57 Custom way back in summer of 67 I used the factory 6 cylinder linkage but had to modify the engine mount side . I used the 6 cyl ball and madeup the necessary bracket to mount it to engine, you might want to think about renforcing the arms on the clutch linkage,depwnding how stiff of clutch pressure plate your going to run! It will make for a fun ride I still LOVE mine ,still got it in garage
HOP