when I was still working, we made bellmouths. my old datsun has side draft Mikuni with radius entry, weber carburetors have radius, ls intakes have radius entry. a bunch of intakes have radius entry. cobras with Weber's, first saw them in the 70's. actually crossfire throttle bodies have radius entry. there's a reason why everyone uses radius entry. reading engineering articles on bell mouth, there all kind of the same. can't really make a bell mouth for crossfire. bell mouthish.
when flow testing head, clay radius entrance is used. natural progression.
started by experimenting with clay shapes. for me the best shape wasn't round. used rod because it was an easy way to add material. there not round anymore. more like the shape of a velocity stack on the inside. outside didn't seem to make much difference.
after months of grinding, welding and testing. ended up with trigger finger on four of my fingers on one hand. better now
I was working on the theory that a non-radius entrance has turbulence and flows like a smaller runner. so I tapered the first inch or so to increase flow and it worked.
made the end runner entrances wider and taller, because they don't really have a radius.
the runners second from the end. smoke and string testing showed the high velocity of air was at the top corner. raised and radius the top and top corner.
the inner four runners were easier. same treatment, tapering like a velocity stack as much as possible.
than the top plate became a problem. worked it out.
truth is, this was months of trial and error. grind a little test, grind more, test. weld more back on, grind test again and again.
for better or worst. it is what it is. stock manifold has limited wall thickness
interesting thing is, if renegade manifold become available again. I'll buy one. tried to buy one before all of this.
aren't you glad you asked.

 

I find that interesting since we spent a lot of time and money when the manifold was under design development back in 2007 with a leading performance manifold manufacturer and found out how much our design gained by doing what we did on the runners. Why GM never did that is a mystery.

 

I'm no expert. no computer designing. built a simple flow bench. just a guy in a garage with time on his hands. something new to learn.
I believe it was part marketing, looks like cross ram. I think gm didn't have max performance in mind.
hope the renegade comes back. I'd buy one.

 

Me too then I'd buy your ported stock intake

 

funny.

 

Granted I'm also searching eBay weekly for a Renegade, and would go that route too if it becomes available