Wanted to get your opinion on some exhaust flow situations i guess i want to call it.

I pick up a Meagan racing header to put a bit of work in it, and have it be better than what the chinese made. Because i did not want to spend a billion for a plug and play header the other 4 or 5 companies out there that make them. I figured if i can buy a cheap header and do a little work, it will work the same as the more exorbitantly priced headers.

ok the issue is the flange has some rather small ports. i want to open them up to either the size of the runners or the size of a OEM gasket. any issues with having the ports/runners larger then the port on the head? i can see velocity go down and flow going up if i open it all the way, but im not sure what the turbulent air from the step will make from small port to big port... i will be welding in a magnaflow cat along with a 2.5" cat back, so from the collector in the header all the way back it will be 2.5".

the other reason i want to open it up all the way is so that i can weld up the runners from the inside to the flange so that i can get a bit stronger area. i have read that the welds break on the primary's do to engine movement. but i have converted the whole front end to poly mounts and there is very very little movement now.

whats your opinion on what i should do?

That is an OEM gasket i laid over the flange to see what im working with here.

 

Interested as well, also I love checking in on your build thread