Jeff,
The hood you are talking about is the R/T hood
Harts resins has it in 24th and 25th scale.
The T/A challenger was built to promote dodge participation in SCCA trans am and the 340 six pack can only be found in that car with the fiberglass hood only
You could get the 340 4bbl with R/T hood or any big block.
Same rules for the shaker hood.
This info is if you are recreating a specific day 1 replica.
It is your model kit so if you just like the R/T hood better leave the 340 6 pack under it and call it a done deal.