We have been doing a lot of cut open and fully ported manifolds lately in addition to our headwork. Here's a couple examples so far, but we will be updating the thread frequently.

Here's some goodies to start:

 

K Series in a DC: Cut Open, Fully Ported, Port Matched TB. Cams were installed too!

 

I have done that with an RBC manifold in the past. Have you done any dyno tests to see if anything was gained from this?

 

The customer did dyno last week, but its skewed results as he had no baseline. He was untuned with basic bolt ons at 183whp. With tuning, TSX cams, 3" Intake, the manifold port, ported ebay throttle body and spacer he made 219whp. The cheap throttle body was not opening completely though. We do have four manifolds out for flow testing now with their stock counterparts though to get numbers.

-Sam

 

We have 4 more manifold coming in this week, and these will all be getting flow numbers from before and after. They will also be getting dyno tested back to back as well!

-Sam

 

I'd love to see some test results. Keep us posted!

 

i personally like to bring the runners to a smooth polish while leaving the plenum smoothed down to about 160 grit.

i am curious to see what a 160/80 grit runner finish would compare to a a polished internal runner.

and this is the only good thing about the stock gsr manifold, the fact that it breaks down into 3 pieces, no cutting required. But reguardless the manifolds look great, are the runners port matched to the heads also..?