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Dart Pro-1 heads... quality control issues? (pics)

2K views 2 replies 2 participants last post by  v8hed 
#1 ·
I just had a set of bare Dart Pro-1 SBC heads delivered from a local dealer. They're the pre-Platinum design with 215cc runners, 64cc chambers and 2.05" intake and 1.60" exhaust.

On unboxing and visually inspecting the castings, I've noticed quite a few issues, which I'm not sure are a problem or not. I'd appreciate input from anyone who is familiar with Dart heads (or new name brand aftermarket heads in general).

The issues I noted are as follows:

1) Valve guides are not all pressed into the castings by a uniform amount... some guides extend into the ports by a small amount, while others do not.

2) There is a green residue around a couple of the guides. Not sure what this is.

3) There is a hand-done etching on one of the castings... not an issue, per se, but what is this for?

4) The transition from the machined area under the seat to the cast area of the bowl is rather abrupt. Is this normal for 'as cast' heads?

5) I was a little surprised at the amount of casting flash around the ports. Again, is thie normal for 'as cast' heads?

6) The sealing face of each casting has some kind of patina on it... not sure if this will simply clean-off (haven't tried yet). Is this normal?

7) Would there be any tangible benefit from addressing points 4 and 5 with a grinder?

I've attached pics below to illustrate all the above points:

























Thanks.
 
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#2 ·
Casting is typical as-cast finish, they figure you are going to hand blend them for better performance but they can be used out of the box. The amount the guide protrudes past the cast surface in the port is different due to casting tolerances, and again the fact that they figure the end user is going to do some porting or blending. It appears they are all pressed in to the same depth on the valvespring side, this is the important side as far as distance is concerned.

Green color on guides is either identifier for part specs of guide, or a preservative, or lube used when pressing guides, but it is nothing to worry about.

The lip under the transition under the seat is another one of those hand blend end user areas.

Not sure what the hand etching is.

The newer Platinum castings are a much cleaner casting, what you have is typical for the older castings.

Patina on the machined surfaces is just typical aluminum oxidation, nothing to worry about.

A good light port job with a carbide cutter and then blending with a cartridge roll will add a decent amount of airflow. I always consider it worth it, especially slimming the guide boss in the ports, and smoothing the transition area and short turn radius of the intake port. Figure 10-15 cfm at the low end, to as much as 25 if you know what you are doing.
 
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