i have a street ported s5 motor. Am considering using these housings now to be p-ported although my builder has cautioned that as the exhaust ports on these housings have been street ported, the exhaust will open about 6mm earlier than had it been stock.

In your opinion, should we rather find a set of stock housings to p-port or is this 6mm not going to cause a problem ?

 

if you're going full PP the old ports will be filled in anyway.

 

I believe most of the time the exhaust on a p-port is opened up alot anyway to let the engine exhale all the extra "air" it sucks in through the very large intake ports.

 

yes, i understand the intake ports will all be filled up. I was talking about the exhaust ports here