I can understand mixing different engines, frames and parts with Hot Rods, because guys from the 50's compiled what ever they could get hold of to buikd a car. But not in a Cobra !
That's like putting a Ford FE/side oiler,................in a Corvette !
I know that Rich Anderson (Gessford machine) built a HEMI, for a customers Cobra.
What ever turns your crank,.... I guess.