I'm current running Trickflow heads with an intake port volume of 195cc's. The intake port measures 2.070" x 1.260" according to Trickflow. Factory flow rating is 254cfm.

On the bench waiting to be installed are a set of Dart Pro 1 heads with an intake port volume of 200cc'c. The ports measure 2.00" x 1.190". I have had them flowed at 276cfm.

So what I had thought would be the case is not. I would have thought the Dart runners would have been a little larger in area but in fact are smaller than the Trickflows. So I guess the difference is in the bowl area. The Darts heads have had some work done to them so I guess they are now larger than 200cc.

Reason this came up is I will have to mate my current intake manifold to the new Dart heads. It is already Extrude Honed but I don't know the measurements. So it is quite posible I will have to open up the Dart heads abit at the entrance to match the intake manifold.

Question is how far into the head to you go for blending purposes. 1/4", 1/2"? I want the intake manifold flow to match the heads and I will get it flowed and may have to open it up some more. I will want it in the 275 to 280cfm range to match the Dart heads. Any thoughts appreciated so that I don't screw things up. Thanks.

 

on the matching of the heads to the intake. blend the opening as far back as possible to get the best transition. and I would say a min. of 1". and yes the darts have a larger bowl area. you can open them up some a the pushrod pinch while you are blending the opening into the runner to help with some small cfm increases in the heads.

good luck

 

Thanks for the reply and information. The intake is on my current motor and still in use. When I do the motor swap I will then know what I'm dealing with.