I pulled my dart 180's off to put on a 400. I figured that I would port them while they were off.

Question 1: Has anyone done this on a set of Dart heads and give me some tips for porting (possibly backing it up with flow numbers)

An interesting thing I discovered is the fact that Dart machines out the area right behind the valve about 3/4". When there is core shift, there is a pronounced ridge betwee the ideal runner and the actual runner. Pictures to follow

 

Porting is a complicated subject and it shouldn't be undertaken by an amatuer (no offense) on the heads you are going to use. I would suggest getting some heads from a local wrecking yard and practice on those. Technique will be the same as will the ideal port shape; also read some books that deal with this and you will see that many of them outline the same port shape to maximize port flow and swirl.

I know this wasn't part of your question, but, also keep in mind that your cam has a lot to do with maximizing your intake charge in the form of overlap.

Have fun!!!

 

I did my 180's about a year ago, however I don't have any timeslips or flow numbers to back anything up. When I did them I port matched them to a 1205 gasket, cleaned up the shortside a little, smoothed out the valve guide boss on the exhaust side and opened up the exhaust bowl a bit. Besides that it was just mainly cleaning up the chambers and polishing stuff up. When the car did run it pulled pretty damn good considering it was running rich as all hell (would foul the plugs in about two weeks) and had a siamesed stock TPI intake on it. Really wish I could get the thing running and check out the LT1 intake.

 

87daddyformula:

Ported junkyard heads, read the books, etc ... I'm still a novice at head porting, but pretty well seasoned in engine building (See BuckeyeROC's engine). Don't let the number of posts fool you.

I spoke with dart briefly about the subject and they said not to touch the short side radius. It feel pretty good to me anyways. They said gasket match and enlarge the walls a bit and do some bowl blending. Pictures soon.

 

No bashing intended at all in my last post...just stating that there is an ideal port shape and all the books tend to be in agreement. I am a Novice when it comes to porting and I plan on using some throw away practice heads.