I want to port some d3 heads this winter and was wondering about the exhaust ports. I know that this is the weak part of these heads and was wondering if this "bump" that is in the bottom of the port when the head is lying flat on the milling surface is the place to start.
Any help or idea's?
go to reincarnation-automotive website, pay the $25 regristration fee and it gives you the web's ultimate authority on porting D3's heads. step by step instructions from probably the best porter of stock heads out there.
i spent the $25 and did my D0VE heads. he shows where and what to grind and where not to grind.
i would recommend that site if you are going to do the porting. best $25 you will spend.
DONT GRIND THAT BUMP!!! Actually called the "tongue"... thats there for a reason. The exaust ports are "ramped" up like that to increase air velocity. If you have a good set of heads ported profesionally, they actually add material to the floor, and grind on the roof of the port. Porting is a fine art. You want to make the head more efficient, not just bigger. Also, around the valves, you could do a bit of smoothing and unshrouding, but make sure to take the same amount of material out of each chamber. The best thing to do if youre unsure about porting is stick to port matching. Get the intake and exaust gaskets you will use, scribe the ports where the edges of the gaskets are. then make the ports flush to the scribe marks.. keep everything smooth and rounded. This is a really good trick on the intake. When doing and intake you want to keep everything "burred" up and rough, this helps atomize the fuel in the air. while on the exaust side, you want to polish or at least make it as smooth as possible, same with the combustion chamber.