Porting Question
Thread Starter
|
New User
Joined: May 2003
Posts: 2
Likes: 0
Porting Question
I have a pair of D2TEAA heads off my '75 390, and on the exhaust side there is a large hump on the floor of the exhaust port that I think would impede exhaust flow. Has anyone tried to remove this, and what kind of trouble or issues have come up? Thank you!
Last edited by gaspoweredsales28; May 21, 2003 at 05:57 PM.
Cargo Master
Joined: Jul 2000
Posts: 2,281
Likes: 18
From: Northern California
Porting Question
The hump on the floor (closest to the chamber) won't make any real difference in flow. You gain much more by working on the roof (it should have a hump in it) and the bowl area and then unshrouding the valves.
I don't know who did the flow tests on this but it was some time ago. I guess the roof is concidered the fast side and that's where the gains are made.
I don't know who did the flow tests on this but it was some time ago. I guess the roof is concidered the fast side and that's where the gains are made.
Porting Question
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
Porting Question
You can't take that hump all the way out anyway. There isn't enough meat. I butchered a set of D2 heads from the scrapyard on purpose to see where the limits are and they have a good bit of meat, just not in that spot.
Senior User
Joined: Nov 2000
Posts: 366
Likes: 0
From: Calgary
Porting Question
I'm pretty sure thats an EGR bump, and it can't be removed. He are the rules of porting that I've came across. Exhaust ports can be polished but with little gain. The bowl where the valves sit in can be ground. Where the machining for the valve ends and the port begins should be radiused. This applies for intake and exhaust. The intake port should be left unpolished. The rough surface contributes to atomization. Any casting flaws should be removed. Enlarging port dimension should be matched with intake/headers to keep a consistent flow.
