Maybe this should go in Q&A...
But since it's a Restoration item, and most of the resellers lurk here... I'll start here.


My question is this... (based on what FAST guys are doing with them)

Are all of the current Repo HP Manifolds "Exact" reproductions internally?

Here is why I ask...
I have spent years in the boating world, where cast iron exhaust manifolds are the norm.
However over the years several aftermarket companies, like GLM, began to manufacture improved replacements
These replacements incorporated internal casting changes that were far superior to the original designs, yet looked exactly the same externally. (Some even cast them in Aluminum) Eventually the original manufacturers also implemented the same internal changes allowing for improved exhaust flow across the board.

From what I've read, the FAST guys have figured out how to make the stock exhaust "Flow Better".

So, my question is...
Has anyone incorporated any of those "changes" into the internal casting of the new Repo HP Manifolds?
If not, why not?
I would think there would be a strong market for anything with improved flow, just like the marine counterparts.

Just wondering.
thx