Roush Technical Question: Series I Plenum.. port or junk?

Just a quick question. Maybe someone out there has faced the same situation.

I am planning on sending out my Series I to be serviced and ported (most likely at Steigemeier). I would like to start running a 75 MM Throttle Body instead of the 70MM I currently have.

My question is: Should I send the stock plenum to be ported out to 75MM? Or should I locate and replace the plenum with the Series IV style plenum piece? I saw them for sale on Haney's website a few months ago.

Any feedback would be appreciated. I am currently running the meter forward kit from Tunable Induction, a 90MM Lightning MAF, followed by the Chicane pipe from the Chicane RIPP kit up to the 70MM TB.

Thanks,

Johan

Gotcha.. I understand the cost aspect of it. So are you saying that a ported Series I inlet would be equivilent to a Series IV Inlet in regards to flow?